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--- a/.gitignore
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+# OS specific files
+.DS_Store
+Thumbs.db
+
+# Project dependencies
+node_modules/
+
+# Distribution files
+dist/
+
+# User defined
+memo.md
--- a/.npmrc
+++ b/.npmrc
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+# only = production
+prefer-offline=true
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
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+# Kyush LLM Router Architecture Document
+
+## Overview
+
+Kyush LLM Router is a proxy server that manages multiple users and routes their requests to various OpenAI-compatible backend APIs. It provides API key-based authentication, user permission management, and usage monitoring through an admin web dashboard.
+
+## System Architecture
+
+```
+┌───────────────────────────────────────────────────────────────────────────┐
+│                              Client Layer                                  │
+├─────────────────────┬───────────────────────────────┬─────────────────────┤
+│  LLM Clients        │  Admin Dashboard              │  Vite Dev Server    │
+│  (OpenAI SDK etc)   │  (Solid.js + Vite)            │  (Port 5173)        │
+└──────────┬──────────┴──────────────┬────────────────┴──────────┬──────────┘
+           │                         │                           │
+           │  OpenAI-Compatible API  │  REST API                 │
+           │  (Port 3000)            │  (Port 3001)              │
+           ▼                         ▼                           │
+┌───────────────────────────────────────────────────────────────────────────┐
+│                         Router Server (Node.js/Express)                    │
+│                              (Port 3000)                                   │
+├───────────────────────────────────────────────────────────────────────────┤
+│  ┌───────────────────────────────────────────────────────────────────┐    │
+│  │  Authentication Middleware                                        │    │
+│  │  - API Key Validation                                             │    │
+│  │  - Rate Limiting                                                  │    │
+│  └───────────────────────────────────────────────────────────────────┘    │
+│  ┌───────────────────────────────────────────────────────────────────┐    │
+│  │  Request Router                                                   │    │
+│  │  - Backend Selection                                              │    │
+│  │  - Load Balancing (optional)                                      │    │
+│  │  - Request/Response Transformation                                │    │
+│  └───────────────────────────────────────────────────────────────────┘    │
+│  ┌───────────────────────────────────────────────────────────────────┐    │
+│  │  Admin API Endpoints (proxied to Vite dev server)                │    │
+│  │  - User Management                                                │    │
+│  │  - Backend Management                                             │    │
+│  │  - Permission Management                                          │    │
+│  │  - Usage Analytics                                                │    │
+│  └───────────────────────────────────────────────────────────────────┘    │
+└────────────────────────────┬──────────────────────────────────────────────┘
+                             │
+           ┌─────────────────┴─────────────────┐
+           ▼                                   ▼
+┌───────────────────────┐         ┌─────────────────────────┐
+│  Core Database        │         │  Analytics Database     │
+│  (SQLite - core.db)   │         │  (SQLite - analytics.db)│
+├───────────────────────┤         ├─────────────────────────┤
+│  - users              │         │  - request_logs         │
+│  - backends           │         │  - usage_stats          │
+│  - permissions        │         │  - backend_metrics      │
+└───────────────────────┘         └─────────────────────────┘
+           │                                   │
+           └─────────────────┬─────────────────┘
+                             ▼
+┌───────────────────────────────────────────────────────────────────────────┐
+│                              Backend Layer                                 │
+├───────────────────────────────────────────────────────────────────────────┤
+│  Multiple OpenAI-Compatible APIs (vLLM, SGLang, etc.)                     │
+└───────────────────────────────────────────────────────────────────────────┘
+```
+
+## Project Structure
+
+```
+kyush-llm-router/
+├── server/
+│   ├── src/
+│   │   ├── index.ts                  # Express app entry point
+│   │   ├── config/
+│   │   │   ├── database.ts           # Core SQLite connection
+│   │   │   └── analytics-db.ts       # Analytics SQLite connection
+│   │   ├── routes/
+│   │   │   ├── api.ts                # OpenAI-compatible API proxy
+│   │   │   ├── admin.ts              # Admin management API
+│   │   │   └── auth.ts               # Authentication middleware
+│   │   ├── models/
+│   │   │   ├── User.ts               # User model
+│   │   │   ├── Backend.ts            # Backend model
+│   │   │   └── Permission.ts         # Permission model
+│   │   ├── analytics/
+│   │   │   ├── RequestLog.ts         # Request log model (analytics DB)
+│   │   │   ├── UsageStats.ts         # Usage stats model (analytics DB)
+│   │   │   └── BackendMetrics.ts     # Backend metrics model
+│   │   ├── services/
+│   │   │   ├── AuthService.ts        # API key validation
+│   │   │   ├── RouterService.ts      # Backend routing logic
+│   │   │   └── AnalyticsService.ts   # Usage tracking
+│   │   └── utils/
+│   │       └── logger.ts             # Logging utility
+│   ├── package.json
+│   └── tsconfig.json
+│
+├── client/
+│   ├── src/
+│   │   ├── index.tsx                 # Solid.js entry point
+│   │   ├── App.tsx                   # Main application component
+│   │   ├── routes/
+│   │   │   ├── Dashboard.tsx         # Main dashboard
+│   │   │   ├── Users.tsx             # User management
+│   │   │   ├── Backends.tsx          # Backend management
+│   │   │   ├── Permissions.tsx       # Permission management
+│   │   │   └── Analytics.tsx         # Usage monitoring
+│   │   ├── components/
+│   │   │   ├── Layout.tsx            # Admin layout
+│   │   │   ├── UserTable.tsx         # User list table
+│   │   │   ├── BackendTable.tsx      # Backend list table
+│   │   │   └── StatsChart.tsx        # Usage chart component
+│   │   ├── api/
+│   │   │   └── client.ts             # API client for admin endpoints
+│   │   └── types/
+│   │       └── index.ts              # TypeScript type definitions
+│   ├── package.json
+│   ├── vite.config.ts
+│   └── tsconfig.json
+│
+├── shared/
+│   └── types.ts                      # Shared type definitions
+│
+├── database/
+│   ├── schema.sql                    # Core database schema
+│   └── analytics-schema.sql          # Analytics database schema
+│
+├── scripts/
+│   └── dev.js                        # Dev server launcher (runs both)
+│
+├── docker-compose.yml                # Docker Compose setup
+├── package.json                      # Root package.json (scripts)
+└── README.md
+```
+
+## Core Components
+
+### 1. Server (Node.js/Express)
+
+#### Authentication Middleware (`src/routes/auth.ts`)
+- Validates API keys from incoming requests
+- Extracts user identity from `Authorization: Bearer <api_key>` header
+- Returns 401 if authentication fails
+- Attaches user info to request object for downstream handlers
+
+#### API Proxy Route (`src/routes/api.ts`)
+```typescript
+// OpenAI-compatible endpoints
+POST /v1/chat/completions
+POST /v1/completions
+GET  /v1/models
+```
+- Forwards requests to selected backend
+- Handles request/response transformation
+- Logs all requests for analytics
+
+#### Admin API Route (`src/routes/admin.ts`)
+```typescript
+// User Management
+POST   /admin/users          # Create user
+GET    /admin/users          # List users
+PUT    /admin/users/:id      # Update user
+DELETE /admin/users/:id      # Delete user
+
+// Backend Management
+POST   /admin/backends       # Add backend
+GET    /admin/backends       # List backends
+PUT    /admin/backends/:id   # Update backend
+DELETE /admin/backends/:id   # Delete backend
+
+// Permission Management
+POST   /admin/permissions    # Grant permission
+DELETE /admin/permissions    # Revoke permission
+GET    /admin/permissions    # List permissions
+
+// Analytics
+GET    /admin/analytics/usage       # Usage statistics
+GET    /admin/analytics/requests    # Request logs
+```
+
+#### Router Service (`src/services/RouterService.ts`)
+- Selects appropriate backend based on:
+  - User's permissions
+  - Backend availability
+  - Load balancing strategy (round-robin, least-loaded)
+- Handles backend failures with retry logic
+
+### 2. Client (Solid.js + Vite)
+
+#### Pages
+- **Dashboard**: Overview of system status, recent activity
+- **Users**: CRUD operations for users, API key generation
+- **Backends**: Manage backend API configurations
+- **Permissions**: Assign/revoke backend access per user
+- **Analytics**: View usage statistics and request logs
+
+#### Key Features
+- Real-time updates via polling or WebSocket (optional)
+- Form validation for user/backend input
+- Error handling with user-friendly messages
+- Responsive design for various screen sizes
+
+### 3. Databases (SQLite)
+
+#### Core Database Schema (core.db)
+
+```sql
+-- Users table
+CREATE TABLE users (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    api_key TEXT UNIQUE NOT NULL,
+    name TEXT NOT NULL,
+    email TEXT,
+    is_active BOOLEAN DEFAULT 1,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+);
+
+-- Backends table
+CREATE TABLE backends (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    name TEXT UNIQUE NOT NULL,
+    base_url TEXT NOT NULL,
+    api_key TEXT,
+    is_active BOOLEAN DEFAULT 1,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+);
+
+-- Permissions table (many-to-many: users ↔ backends)
+CREATE TABLE permissions (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    backend_id INTEGER NOT NULL,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    FOREIGN KEY (user_id) REFERENCES users(id),
+    FOREIGN KEY (backend_id) REFERENCES backends(id),
+    UNIQUE(user_id, backend_id)
+);
+
+-- Indexes for performance
+CREATE INDEX idx_users_api_key ON users(api_key);
+CREATE INDEX idx_permissions_user ON permissions(user_id);
+CREATE INDEX idx_permissions_backend ON permissions(backend_id);
+```
+
+#### Analytics Database Schema (analytics.db)
+
+```sql
+-- Request logs table
+CREATE TABLE request_logs (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    backend_id INTEGER NOT NULL,
+    endpoint TEXT NOT NULL,
+    request_model TEXT,
+    response_model TEXT,
+    prompt_tokens INTEGER,
+    completion_tokens INTEGER,
+    total_tokens INTEGER,
+    status_code INTEGER,
+    response_time_ms INTEGER,
+    error_message TEXT,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    FOREIGN KEY (user_id) REFERENCES users(id),
+    FOREIGN KEY (backend_id) REFERENCES backends(id)
+);
+
+-- Usage stats table (aggregated daily)
+CREATE TABLE usage_stats (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    backend_id INTEGER NOT NULL,
+    date DATE NOT NULL,
+    total_requests INTEGER DEFAULT 0,
+    total_tokens INTEGER DEFAULT 0,
+    FOREIGN KEY (user_id) REFERENCES users(id),
+    FOREIGN KEY (backend_id) REFERENCES backends(id),
+    UNIQUE(user_id, backend_id, date)
+);
+
+-- Backend metrics table (aggregated metrics per backend)
+CREATE TABLE backend_metrics (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    backend_id INTEGER NOT NULL,
+    date DATE NOT NULL,
+    total_requests INTEGER DEFAULT 0,
+    total_tokens INTEGER DEFAULT 0,
+    avg_response_time_ms REAL DEFAULT 0,
+    error_count INTEGER DEFAULT 0,
+    success_rate REAL DEFAULT 1.0,
+    FOREIGN KEY (backend_id) REFERENCES backends(id),
+    UNIQUE(backend_id, date)
+);
+
+-- Indexes for performance
+CREATE INDEX idx_request_logs_user ON request_logs(user_id);
+CREATE INDEX idx_request_logs_backend ON request_logs(backend_id);
+CREATE INDEX idx_request_logs_date ON request_logs(created_at);
+CREATE INDEX idx_usage_stats_user ON usage_stats(user_id);
+CREATE INDEX idx_usage_stats_date ON usage_stats(date);
+CREATE INDEX idx_backend_metrics_backend ON backend_metrics(backend_id);
+CREATE INDEX idx_backend_metrics_date ON backend_metrics(date);
+```
+
+## API Design
+
+### OpenAI-Compatible API Proxy
+
+The router exposes the same API interface as OpenAI, making it easy for clients to integrate.
+
+#### Example Request
+```bash
+curl http://localhost:3000/v1/chat/completions \
+  -H "Authorization: Bearer <user_api_key>" \
+  -H "Content-Type: application/json" \
+  -d '{
+    "model": "llama-3",
+    "messages": [{"role": "user", "content": "Hello"}]
+  }'
+```
+
+#### Example Response
+```json
+{
+  "id": "chatcmpl-xxx",
+  "object": "chat.completion",
+  "created": 1234567890,
+  "model": "llama-3",
+  "choices": [{
+    "index": 0,
+    "message": {
+      "role": "assistant",
+      "content": "Hello! How can I help you?"
+    },
+    "finish_reason": "stop"
+  }],
+  "usage": {
+    "prompt_tokens": 10,
+    "completion_tokens": 15,
+    "total_tokens": 25
+  }
+}
+```
+
+### Admin API
+
+#### Create User
+```bash
+POST /admin/users
+Content-Type: application/json
+
+{
+  "name": "John Doe",
+  "email": "john@example.com"
+}
+
+Response: {
+  "id": 1,
+  "name": "John Doe",
+  "api_key": "sk-xxx...",
+  "created_at": "2024-01-01T00:00:00Z"
+}
+```
+
+#### Add Backend
+```bash
+POST /admin/backends
+Content-Type: application/json
+
+{
+  "name": "vLLM Server 1",
+  "base_url": "http://localhost:8000/v1",
+  "api_key": "backend-key-xxx"
+}
+```
+
+## Security Considerations
+
+1. **API Key Storage**: API keys are stored hashed in the database
+2. **Transport Security**: Use HTTPS in production
+3. **Rate Limiting**: Implement per-user rate limits
+4. **Input Validation**: Validate all admin API inputs
+5. **CORS**: Configure CORS for admin dashboard only
+
+## Deployment
+
+### Development
+
+Run both server and client with a single command:
+
+```bash
+npm run dev
+```
+
+This starts:
+- Express server on port 3000
+- Vite dev server on port 3001 (admin API routes proxied from Express)
+
+### Docker Compose
+
+```yaml
+version: '3.8'
+
+services:
+  router:
+    build: .
+    ports:
+      - "3000:3000"
+    environment:
+      - NODE_ENV=production
+      - SERVER_PORT=3000
+      - CLIENT_PORT=3001
+      - CORE_DB_PATH=/data/core.db
+      - ANALYTICS_DB_PATH=/data/analytics.db
+    volumes:
+      - router-data:/data
+    restart: unless-stopped
+
+volumes:
+  router-data:
+```
+
+### Environment Variables
+
+| Variable | Description | Default |
+|----------|-------------|---------|
+| `SERVER_PORT` | Express server port | `3000` |
+| `CLIENT_PORT` | Vite dev server port | `3001` |
+| `CORE_DB_PATH` | Core database path | `./data/core.db` |
+| `ANALYTICS_DB_PATH` | Analytics database path | `./data/analytics.db` |
+| `ADMIN_PASSWORD` | Admin dashboard password | (required) |
+
+## Development Roadmap
+
+### Phase 1: Core Infrastructure
+- [ ] Set up Express server with TypeScript
+- [ ] Implement SQLite database schema
+- [ ] Create user and backend models
+- [ ] Implement API key authentication
+
+### Phase 2: API Proxy
+- [ ] Implement OpenAI-compatible API endpoints
+- [ ] Add request forwarding to backends
+- [ ] Implement basic routing logic
+- [ ] Add request logging
+
+### Phase 3: Admin API
+- [ ] Implement CRUD endpoints for users
+- [ ] Implement CRUD endpoints for backends
+- [ ] Implement permission management
+- [ ] Add usage analytics endpoints
+
+### Phase 4: Admin Dashboard
+- [ ] Set up Solid.js + Vite project
+- [ ] Create user management UI
+- [ ] Create backend management UI
+- [ ] Create permission management UI
+- [ ] Create analytics dashboard
+
+### Phase 5: Advanced Features
+- [ ] Add rate limiting
+- [ ] Implement load balancing
+- [ ] Add WebSocket for real-time updates
+- [ ] Implement backend health checks
+
+## Technology Stack Summary
+
+| Component | Technology |
+|-----------|------------|
+| Backend | Node.js 18+, Express.js, TypeScript |
+| Core Database | SQLite (better-sqlite3) |
+| Analytics Database | SQLite (better-sqlite3) |
+| Frontend | Solid.js, Vite, TypeScript |
+| HTTP Client | Axios/Fetch |
+| Charts | Chart.js or Solid-chart |
+| Styling | Tailwind CSS or CSS Modules |
+| Validation | Zod |
+| Testing | Vitest (frontend), Jest (backend) |
+| Dev Server | Concurrently for running both servers |
--- a/33
+++ b/33
@ -0,0 +1,33 @@
+FROM node:18-alpine
+
+WORKDIR /app
+
+# Install curl for healthcheck
+RUN apk add --no-cache curl
+
+# Copy package files
+COPY package.json package-lock.json* ./
+COPY server/package.json ./server/
+COPY client/package.json ./client/
+
+# Install dependencies
+RUN npm ci
+
+# Copy source code
+COPY server/ ./server/
+COPY client/ ./client/
+COPY scripts/ ./scripts/
+COPY database/ ./database/
+
+# Build client
+RUN npm run build --workspace=client
+
+# Build server
+RUN npm run build --workspace=server
+
+# Create data directory
+RUN mkdir -p /data
+
+EXPOSE 3000
+
+CMD ["npm", "start"]
--- a/README.md
+++ b/README.md
@ -0,0 +1,121 @@
+# Kyush LLM Router
+
+Multi-user LLM routing proxy with API key management and usage monitoring.
+
+## Features
+
+- **Multi-user support**: Manage multiple users with individual API keys
+- **Backend routing**: Route requests to multiple OpenAI-compatible backends (vLLM, SGLang, etc.)
+- **Permission management**: Control which users can access which backends
+- **Usage monitoring**: Track request logs, token usage, and backend metrics
+- **Admin dashboard**: Web UI for managing users, backends, and permissions
+
+## Architecture
+
+```
+┌─────────────────┐     ┌──────────────────────────────────────┐
+│  LLM Clients    │────▶│  Router Server (Port 3000)           │
+│  (OpenAI SDK)   │     │  - Authentication                    │
+└─────────────────┘     │  - Request Routing                   │
+                        │  - Admin API                         │
+                        └─────────────────┬────────────────────┘
+                                          │
+                        ┌─────────────────┴────────────────────┐
+                        ▼                                      ▼
+                ┌─────────────────┐                  ┌─────────────────┐
+                │  core.db        │                  │  analytics.db   │
+                │  - users        │                  │  - request_logs │
+                │  - backends     │                  │  - usage_stats  │
+                │  - permissions  │                  │  - metrics      │
+                └─────────────────┘                  └─────────────────┘
+```
+
+## Quick Start
+
+### Development
+
+1. Install dependencies:
+```bash
+npm install
+```
+
+2. Start development servers:
+```bash
+npm run dev
+```
+
+This starts:
+- Express API server on http://localhost:3000
+- Vite admin dashboard on http://localhost:3001
+
+### Production with Docker
+
+1. Build and run:
+```bash
+docker-compose up -d
+```
+
+2. Set admin password via environment variable:
+```bash
+ADMIN_PASSWORD=your_secure_password docker-compose up -d
+```
+
+## Project Structure
+
+```
+kyush-llm-router/
+├── server/           # Express backend
+├── client/           # Solid.js admin dashboard
+├── database/         # SQL schema files
+├── scripts/          # Development scripts
+└── docs/             # Documentation
+```
+
+## API Endpoints
+
+### OpenAI-Compatible API (Port 3000)
+
+```
+POST /v1/chat/completions
+POST /v1/completions
+GET  /v1/models
+```
+
+### Admin API (Port 3001)
+
+```
+# User Management
+POST   /admin/users
+GET    /admin/users
+PUT    /admin/users/:id
+DELETE /admin/users/:id
+
+# Backend Management
+POST   /admin/backends
+GET    /admin/backends
+PUT    /admin/backends/:id
+DELETE /admin/backends/:id
+
+# Permission Management
+POST   /admin/permissions
+DELETE /admin/permissions
+GET    /admin/permissions
+
+# Analytics
+GET    /admin/analytics/usage
+GET    /admin/analytics/requests
+```
+
+## Environment Variables
+
+| Variable | Description | Default |
+|----------|-------------|---------|
+| `SERVER_PORT` | Express server port | `3000` |
+| `CLIENT_PORT` | Vite dev server port | `3001` |
+| `CORE_DB_PATH` | Core database path | `./data/core.db` |
+| `ANALYTICS_DB_PATH` | Analytics database path | `./data/analytics.db` |
+| `ADMIN_PASSWORD` | Admin dashboard password | Required |
+
+## License
+
+MIT
--- a/client/index.html
+++ b/client/index.html
@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>LLM Router Admin</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/index.tsx"></script>
+  </body>
+</html>
--- a/client/package.json
+++ b/client/package.json
@ -0,0 +1,25 @@
+{
+  "name": "client",
+  "version": "1.0.0",
+  "description": "LLM Router Admin Dashboard",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "vite build",
+    "preview": "vite preview",
+    "typecheck": "tsc --noEmit"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "MIT",
+  "dependencies": {
+    "solid-js": "^1.9.11",
+    "@solidjs/router": "^0.15.4"
+  },
+  "devDependencies": {
+    "vite": "^7.3.1",
+    "vite-plugin-solid": "^2.11.10",
+    "typescript": "^5.9.3",
+    "@types/node": "^25.3.3"
+  }
+}
--- a/client/pnpm-lock.yaml
+++ b/client/pnpm-lock.yaml
--- a/client/src/App.tsx
+++ b/client/src/App.tsx
@ -0,0 +1,18 @@
+import { Router, Route } from '@solidjs/router';
+import { Dashboard } from './routes/Dashboard';
+import { Users } from './routes/Users';
+import { Backends } from './routes/Backends';
+import { Permissions } from './routes/Permissions';
+import { Analytics } from './routes/Analytics';
+
+export default function App() {
+  return (
+    <Router>
+      <Route path="/" component={Dashboard} />
+      <Route path="/users" component={Users} />
+      <Route path="/backends" component={Backends} />
+      <Route path="/permissions" component={Permissions} />
+      <Route path="/analytics" component={Analytics} />
+    </Router>
+  );
+}
--- a/client/src/api/client.ts
+++ b/client/src/api/client.ts
@ -0,0 +1,80 @@
+import type { User, Backend, Permission, RequestLog, UsageStats, BackendMetrics } from '../types';
+
+const API_BASE = '/api';
+
+async function fetchJson<T>(url: string, options: RequestInit = {}): Promise<T> {
+  const response = await fetch(url, {
+    ...options,
+    headers: {
+      'Content-Type': 'application/json',
+      ...options.headers,
+    },
+  });
+
+  if (!response.ok) {
+    const error = await response.json().catch(() => ({ error: 'Request failed' }));
+    throw new Error(error.error || `HTTP ${response.status}`);
+  }
+
+  if (response.status === 204) {
+    return {} as T;
+  }
+
+  return response.json();
+}
+
+export const api = {
+  users: {
+    getAll: (): Promise<User[]> => fetchJson<User[]>(`${API_BASE}/admin/users`),
+    getById: (id: number): Promise<User> => fetchJson<User>(`${API_BASE}/admin/users/${id}`),
+    create: (data: { name: string; email?: string }): Promise<User> =>
+      fetchJson<User>(`${API_BASE}/admin/users`, { method: 'POST', body: JSON.stringify(data) }),
+    update: (id: number, data: Partial<User>): Promise<User> =>
+      fetchJson<User>(`${API_BASE}/admin/users/${id}`, { method: 'PUT', body: JSON.stringify(data) }),
+    delete: (id: number): Promise<void> =>
+      fetchJson<void>(`${API_BASE}/admin/users/${id}`, { method: 'DELETE' }),
+    regenerateApiKey: (id: number): Promise<User> =>
+      fetchJson<User>(`${API_BASE}/admin/users/${id}/regenerate-api-key`, { method: 'POST' }),
+  },
+
+  backends: {
+    getAll: (): Promise<Backend[]> => fetchJson<Backend[]>(`${API_BASE}/admin/backends`),
+    getById: (id: number): Promise<Backend> => fetchJson<Backend>(`${API_BASE}/admin/backends/${id}`),
+    create: (data: { name: string; base_url: string; api_key?: string }): Promise<Backend> =>
+      fetchJson<Backend>(`${API_BASE}/admin/backends`, { method: 'POST', body: JSON.stringify(data) }),
+    update: (id: number, data: Partial<Backend>): Promise<Backend> =>
+      fetchJson<Backend>(`${API_BASE}/admin/backends/${id}`, { method: 'PUT', body: JSON.stringify(data) }),
+    delete: (id: number): Promise<void> =>
+      fetchJson<void>(`${API_BASE}/admin/backends/${id}`, { method: 'DELETE' }),
+  },
+
+  permissions: {
+    getAll: (): Promise<Permission[]> => fetchJson<Permission[]>(`${API_BASE}/admin/permissions`),
+    getByUser: (userId: number): Promise<Permission[]> =>
+      fetchJson<Permission[]>(`${API_BASE}/admin/permissions/user/${userId}`),
+    getByBackend: (backendId: number): Promise<Permission[]> =>
+      fetchJson<Permission[]>(`${API_BASE}/admin/permissions/backend/${backendId}`),
+    create: (data: { user_id: number; backend_id: number }): Promise<Permission> =>
+      fetchJson<Permission>(`${API_BASE}/admin/permissions`, { method: 'POST', body: JSON.stringify(data) }),
+    delete: (userId: number, backendId: number): Promise<void> =>
+      fetchJson<void>(`${API_BASE}/admin/permissions?user_id=${userId}&backend_id=${backendId}`, { method: 'DELETE' }),
+  },
+
+  analytics: {
+    getUsage: (userId?: number, backendId?: number, days: number = 30): Promise<UsageStats[]> => {
+      const params = new URLSearchParams();
+      if (userId) params.append('userId', String(userId));
+      if (backendId) params.append('backendId', String(backendId));
+      params.append('days', String(days));
+      return fetchJson<UsageStats[]>(`${API_BASE}/admin/analytics/usage?${params}`);
+    },
+    getRequests: (limit: number = 100, offset: number = 0): Promise<RequestLog[]> =>
+      fetchJson<RequestLog[]>(`${API_BASE}/admin/analytics/requests?limit=${limit}&offset=${offset}`),
+    getMetrics: (backendId?: number, days: number = 30): Promise<BackendMetrics[]> => {
+      const params = new URLSearchParams();
+      if (backendId) params.append('backendId', String(backendId));
+      params.append('days', String(days));
+      return fetchJson<BackendMetrics[]>(`${API_BASE}/admin/analytics/metrics?${params}`);
+    },
+  },
+};
--- a/client/src/components/Layout.tsx
+++ b/client/src/components/Layout.tsx
@ -0,0 +1,55 @@
+import { Component, JSX, ParentComponent } from 'solid-js';
+import { useLocation } from '@solidjs/router';
+
+interface LayoutProps {
+  children: JSX.Element;
+}
+
+const navItems = [
+  { path: '/', label: 'Dashboard', icon: '📊' },
+  { path: '/users', label: 'Users', icon: '👥' },
+  { path: '/backends', label: 'Backends', icon: '🔧' },
+  { path: '/permissions', label: 'Permissions', icon: '🔐' },
+  { path: '/analytics', label: 'Analytics', icon: '📈' },
+];
+
+export const Layout: ParentComponent<LayoutProps> = (props) => {
+  const location = useLocation();
+
+  return (
+    <div style={{ display: 'flex', 'min-height': '100vh', 'font-family': 'system-ui, sans-serif' }}>
+      <aside style={{
+        width: '250px',
+        background: '#1e293b',
+        color: 'white',
+        padding: '20px',
+      }}>
+        <h1 style={{ margin: '0 0 30px 0', 'font-size': '1.5rem' }}>LLM Router</h1>
+        <nav style={{ display: 'flex', 'flex-direction': 'column', gap: '10px' }}>
+          {navItems.map(item => (
+            <a
+              href={item.path}
+              style={{
+                display: 'flex',
+                'align-items': 'center',
+                gap: '10px',
+                padding: '12px 15px',
+                background: location.pathname === item.path ? '#3b82f6' : 'transparent',
+                color: 'white',
+                'text-decoration': 'none',
+                'border-radius': '8px',
+                transition: 'background 0.2s',
+              }}
+            >
+              <span>{item.icon}</span>
+              <span>{item.label}</span>
+            </a>
+          ))}
+        </nav>
+      </aside>
+      <main style={{ flex: 1, padding: '30px', background: '#f1f5f9' }}>
+        {props.children}
+      </main>
+    </div>
+  );
+};
--- a/client/src/index.tsx
+++ b/client/src/index.tsx
@ -0,0 +1,8 @@
+import { render } from 'solid-js/web';
+import App from './App';
+
+const root = document.getElementById('root');
+
+if (root) {
+  render(() => <App />, root);
+}
--- a/client/src/routes/Analytics.tsx
+++ b/client/src/routes/Analytics.tsx
@ -0,0 +1,108 @@
+import { Component, createResource, For } from 'solid-js';
+import { api } from '../api/client';
+import type { RequestLog, UsageStats, BackendMetrics } from '../types';
+import { Layout } from '../components/Layout';
+
+export const Analytics: Component = () => {
+  const [requests] = createResource(() => api.analytics.getRequests(50));
+  const [usage] = createResource(() => api.analytics.getUsage(undefined, undefined, 7));
+  const [metrics] = createResource(() => api.analytics.getMetrics(undefined, 7));
+
+  return (
+    <Layout>
+      <div style={{ padding: '30px' }}>
+        <h2 style={{ margin: '0 0 20px 0' }}>Analytics</h2>
+
+        <div style={{ display: 'grid', 'grid-template-columns': 'repeat(auto-fit, minmax(300px, 1fr))', gap: '20px', 'margin-bottom': '30px' }}>
+          <div style={{ background: 'white', padding: '20px', 'border-radius': '8px', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
+            <h3 style={{ margin: '0 0 15px 0', 'font-size': '0.9rem', color: '#64748b' }}>Recent Requests</h3>
+            <div style={{ 'max-height': '300px', overflow: 'auto' }}>
+              {requests.loading ? (
+                <p>Loading...</p>
+              ) : (
+                <table style={{ width: '100%', 'font-size': '0.85rem' }}>
+                  <thead>
+                    <tr style={{ 'border-bottom': '2px solid #e2e8f0' }}>
+                      <th style={{ 'text-align': 'left', padding: '8px' }}>User</th>
+                      <th style={{ 'text-align': 'left', padding: '8px' }}>Tokens</th>
+                      <th style={{ 'text-align': 'left', padding: '8px' }}>Status</th>
+                    </tr>
+                  </thead>
+                  <tbody>
+                    <For each={requests()}>{(req) => (
+                      <tr style={{ 'border-bottom': '1px solid #e2e8f0' }}>
+                        <td style={{ padding: '8px' }}>{req.user_id}</td>
+                        <td style={{ padding: '8px' }}>{req.total_tokens || 0}</td>
+                        <td style={{ padding: '8px', color: req.status_code >= 400 ? '#ef4444' : '#22c55e' }}>{req.status_code}</td>
+                      </tr>
+                    )}</For>
+                  </tbody>
+                </table>
+              )}
+            </div>
+          </div>
+
+          <div style={{ background: 'white', padding: '20px', 'border-radius': '8px', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
+            <h3 style={{ margin: '0 0 15px 0', 'font-size': '0.9rem', color: '#64748b' }}>Usage Stats (7 days)</h3>
+            <div style={{ 'max-height': '300px', overflow: 'auto' }}>
+              {usage.loading ? (
+                <p>Loading...</p>
+              ) : (
+                <table style={{ width: '100%', 'font-size': '0.85rem' }}>
+                  <thead>
+                    <tr style={{ 'border-bottom': '2px solid #e2e8f0' }}>
+                      <th style={{ 'text-align': 'left', padding: '8px' }}>Date</th>
+                      <th style={{ 'text-align': 'left', padding: '8px' }}>Requests</th>
+                      <th style={{ 'text-align': 'left', padding: '8px' }}>Tokens</th>
+                    </tr>
+                  </thead>
+                  <tbody>
+                    <For each={usage()}>{(stat) => (
+                      <tr style={{ 'border-bottom': '1px solid #e2e8f0' }}>
+                        <td style={{ padding: '8px' }}>{stat.date}</td>
+                        <td style={{ padding: '8px' }}>{stat.total_requests}</td>
+                        <td style={{ padding: '8px' }}>{stat.total_tokens}</td>
+                      </tr>
+                    )}</For>
+                  </tbody>
+                </table>
+              )}
+            </div>
+          </div>
+        </div>
+
+        <div style={{ background: 'white', padding: '20px', 'border-radius': '8px', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
+          <h3 style={{ margin: '0 0 15px 0', 'font-size': '0.9rem', color: '#64748b' }}>Backend Metrics (7 days)</h3>
+          <div style={{ 'max-height': '300px', overflow: 'auto' }}>
+            {metrics.loading ? (
+              <p>Loading...</p>
+            ) : (
+              <table style={{ width: '100%', 'font-size': '0.85rem' }}>
+                <thead>
+                  <tr style={{ 'border-bottom': '2px solid #e2e8f0' }}>
+                    <th style={{ 'text-align': 'left', padding: '8px' }}>Date</th>
+                    <th style={{ 'text-align': 'left', padding: '8px' }}>Backend</th>
+                    <th style={{ 'text-align': 'left', padding: '8px' }}>Requests</th>
+                    <th style={{ 'text-align': 'left', padding: '8px' }}>Avg Response (ms)</th>
+                    <th style={{ 'text-align': 'left', padding: '8px' }}>Success Rate</th>
+                  </tr>
+                </thead>
+                <tbody>
+                  <For each={metrics()}>{(metric) => (
+                    <tr style={{ 'border-bottom': '1px solid #e2e8f0' }}>
+                      <td style={{ padding: '8px' }}>{metric.date}</td>
+                      <td style={{ padding: '8px' }}>{metric.backend_id}</td>
+                      <td style={{ padding: '8px' }}>{metric.total_requests}</td>
+                      <td style={{ padding: '8px' }}>{metric.avg_response_time_ms?.toFixed(1) || 0}</td>
+                      <td style={{ padding: '8px' }}>{(metric.success_rate * 100).toFixed(1)}%</td>
+                    </tr>
+                  )}</For>
+                </tbody>
+              </table>
+            )}
+          </div>
+        </div>
+      </div>
+    </Layout>
+  );
+};
--- a/client/src/routes/Backends.tsx
+++ b/client/src/routes/Backends.tsx
@ -0,0 +1,135 @@
+import { Component, createResource, For, createSignal } from 'solid-js';
+import { api } from '../api/client';
+import type { Backend } from '../types';
+import { Layout } from '../components/Layout';
+
+export const Backends: Component = () => {
+  const [backends, { refetch }] = createResource(() => api.backends.getAll());
+  const [showModal, setShowModal] = createSignal(false);
+  const [formData, setFormData] = createSignal({ name: '', base_url: '', api_key: '' });
+
+  const handleSubmit = async (e: Event) => {
+    e.preventDefault();
+    const { name, base_url, api_key } = formData();
+    if (!name.trim() || !base_url.trim()) return;
+
+    await api.backends.create({ name: name.trim(), base_url: base_url.trim(), api_key: api_key.trim() || undefined });
+    setFormData({ name: '', base_url: '', api_key: '' });
+    setShowModal(false);
+    refetch();
+  };
+
+  const handleDelete = async (backendId: number) => {
+    if (!confirm('Are you sure you want to delete this backend?')) return;
+    await api.backends.delete(backendId);
+    refetch();
+  };
+
+  return (
+    <Layout>
+      <div style={{ padding: '30px' }}>
+        <div style={{ display: 'flex', 'justify-content': 'space-between', 'align-items': 'center', 'margin-bottom': '20px' }}>
+          <h2 style={{ margin: 0 }}>Backends</h2>
+          <button
+            onClick={() => setShowModal(true)}
+            style={{ padding: '10px 20px', background: '#3b82f6', color: 'white', border: 'none', 'border-radius': '6px', cursor: 'pointer' }}
+          >
+            Add Backend
+          </button>
+        </div>
+
+        {backends.loading ? (
+          <p>Loading...</p>
+        ) : (
+          <table style={{ width: '100%', 'border-collapse': 'collapse', background: 'white', 'border-radius': '8px', overflow: 'hidden', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
+            <thead style={{ background: '#f8fafc' }}>
+              <tr>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>ID</th>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>Name</th>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>Base URL</th>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>Status</th>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>Actions</th>
+              </tr>
+            </thead>
+            <tbody>
+              <For each={backends()}>{(backend) => (
+                <tr style={{ 'border-bottom': '1px solid #e2e8f0' }}>
+                  <td style={{ padding: '12px' }}>{backend.id}</td>
+                  <td style={{ padding: '12px' }}>{backend.name}</td>
+                  <td style={{ padding: '12px', 'font-family': 'monospace', 'font-size': '0.85rem' }}>{backend.base_url}</td>
+                  <td style={{ padding: '12px', color: backend.is_active ? '#22c55e' : '#ef4444' }}>
+                    {backend.is_active ? 'Active' : 'Inactive'}
+                  </td>
+                  <td style={{ padding: '12px' }}>
+                    <button
+                      onClick={() => handleDelete(backend.id)}
+                      style={{ padding: '4px 8px', background: '#ef4444', color: 'white', border: 'none', 'border-radius': '4px', cursor: 'pointer', 'font-size': '0.8rem' }}
+                    >
+                      Delete
+                    </button>
+                  </td>
+                </tr>
+              )}</For>
+            </tbody>
+          </table>
+        )}
+
+        {showModal() && (
+          <div style={{ position: 'fixed', inset: 0, background: 'rgba(0,0,0,0.5)', display: 'flex', 'align-items': 'center', 'justify-content': 'center', 'z-index': 1000 }}>
+            <div style={{ background: 'white', padding: '30px', 'border-radius': '8px', width: '500px' }}>
+              <h3 style={{ margin: '0 0 20px 0' }}>Add New Backend</h3>
+              <form onSubmit={handleSubmit}>
+                <div style={{ 'margin-bottom': '15px' }}>
+                  <label style={{ display: 'block', 'margin-bottom': '5px', 'font-weight': 'bold' }}>Name *</label>
+                  <input
+                    type="text"
+                    value={formData().name}
+                    onInput={(e) => setFormData({ ...formData(), name: e.target.value })}
+                    style={{ width: '100%', padding: '8px', border: '1px solid #cbd5e1', 'border-radius': '4px', 'box-sizing': 'border-box' }}
+                    required
+                  />
+                </div>
+                <div style={{ 'margin-bottom': '15px' }}>
+                  <label style={{ display: 'block', 'margin-bottom': '5px', 'font-weight': 'bold' }}>Base URL *</label>
+                  <input
+                    type="text"
+                    value={formData().base_url}
+                    onInput={(e) => setFormData({ ...formData(), base_url: e.target.value })}
+                    placeholder="http://localhost:8000/v1"
+                    style={{ width: '100%', padding: '8px', border: '1px solid #cbd5e1', 'border-radius': '4px', 'box-sizing': 'border-box' }}
+                    required
+                  />
+                </div>
+                <div style={{ 'margin-bottom': '20px' }}>
+                  <label style={{ display: 'block', 'margin-bottom': '5px', 'font-weight': 'bold' }}>API Key (optional)</label>
+                  <input
+                    type="text"
+                    value={formData().api_key}
+                    onInput={(e) => setFormData({ ...formData(), api_key: e.target.value })}
+                    placeholder="Backend API key if required"
+                    style={{ width: '100%', padding: '8px', border: '1px solid #cbd5e1', 'border-radius': '4px', 'box-sizing': 'border-box' }}
+                  />
+                </div>
+                <div style={{ display: 'flex', gap: '10px', 'justify-content': 'flex-end' }}>
+                  <button
+                    type="button"
+                    onClick={() => setShowModal(false)}
+                    style={{ padding: '8px 16px', background: '#e2e8f0', border: 'none', 'border-radius': '4px', cursor: 'pointer' }}
+                  >
+                    Cancel
+                  </button>
+                  <button
+                    type="submit"
+                    style={{ padding: '8px 16px', background: '#3b82f6', color: 'white', border: 'none', 'border-radius': '4px', cursor: 'pointer' }}
+                  >
+                    Create
+                  </button>
+                </div>
+              </form>
+            </div>
+          </div>
+        )}
+      </div>
+    </Layout>
+  );
+};
--- a/client/src/routes/Dashboard.tsx
+++ b/client/src/routes/Dashboard.tsx
@ -0,0 +1,70 @@
+import { Component, createResource, For } from 'solid-js';
+import { api } from '../api/client';
+import type { User, Backend, RequestLog } from '../types';
+import { Layout } from '../components/Layout';
+
+export const Dashboard: Component = () => {
+  const [data, { refetch }] = createResource(async () => ({
+    users: await api.users.getAll(),
+    backends: await api.backends.getAll(),
+    recentRequests: await api.analytics.getRequests(10),
+  }));
+
+  return (
+    <Layout>
+      <div style={{ padding: '30px' }}>
+        <h2 style={{ margin: '0 0 20px 0' }}>Dashboard</h2>
+
+        <div style={{ display: 'grid', 'grid-template-columns': 'repeat(auto-fit, minmax(200px, 1fr))', gap: '20px', 'margin-bottom': '30px' }}>
+          <div style={{ background: 'white', padding: '20px', 'border-radius': '8px', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
+            <h3 style={{ margin: '0 0 10px 0', 'font-size': '0.9rem', color: '#64748b' }}>Total Users</h3>
+            <p style={{ margin: 0, 'font-size': '2rem', 'font-weight': 'bold' }}>{data()?.users.length || 0}</p>
+          </div>
+          <div style={{ background: 'white', padding: '20px', 'border-radius': '8px', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
+            <h3 style={{ margin: '0 0 10px 0', 'font-size': '0.9rem', color: '#64748b' }}>Active Backends</h3>
+            <p style={{ margin: 0, 'font-size': '2rem', 'font-weight': 'bold' }}>{data()?.backends.filter(b => b.is_active).length || 0}</p>
+          </div>
+          <div style={{ background: 'white', padding: '20px', 'border-radius': '8px', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
+            <h3 style={{ margin: '0 0 10px 0', 'font-size': '0.9rem', color: '#64748b' }}>Recent Requests</h3>
+            <p style={{ margin: 0, 'font-size': '2rem', 'font-weight': 'bold' }}>{data()?.recentRequests.length || 0}</p>
+          </div>
+        </div>
+
+        <div style={{ background: 'white', padding: '20px', 'border-radius': '8px', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
+          <div style={{ display: 'flex', 'justify-content': 'space-between', 'align-items': 'center', 'margin-bottom': '15px' }}>
+            <h3 style={{ margin: 0 }}>Recent Requests</h3>
+            <button onClick={() => refetch()} style={{ padding: '8px 16px', background: '#3b82f6', color: 'white', border: 'none', 'border-radius': '6px', cursor: 'pointer' }}>
+              Refresh
+            </button>
+          </div>
+          {data()?.recentRequests.length === 0 ? (
+            <p style={{ color: '#64748b' }}>No requests yet</p>
+          ) : (
+            <table style={{ width: '100%', 'border-collapse': 'collapse' }}>
+              <thead>
+                <tr style={{ 'border-bottom': '2px solid #e2e8f0' }}>
+                  <th style={{ 'text-align': 'left', padding: '10px', color: '#64748b' }}>User ID</th>
+                  <th style={{ 'text-align': 'left', padding: '10px', color: '#64748b' }}>Backend</th>
+                  <th style={{ 'text-align': 'left', padding: '10px', color: '#64748b' }}>Model</th>
+                  <th style={{ 'text-align': 'left', padding: '10px', color: '#64748b' }}>Status</th>
+                  <th style={{ 'text-align': 'left', padding: '10px', color: '#64748b' }}>Time</th>
+                </tr>
+              </thead>
+              <tbody>
+                <For each={data()?.recentRequests}>{(request) => (
+                  <tr style={{ 'border-bottom': '1px solid #e2e8f0' }}>
+                    <td style={{ padding: '10px' }}>{request.user_id}</td>
+                    <td style={{ padding: '10px' }}>{request.backend_id}</td>
+                    <td style={{ padding: '10px' }}>{request.request_model || '-'}</td>
+                    <td style={{ padding: '10px', color: request.status_code >= 400 ? '#ef4444' : '#22c55e' }}>{request.status_code}</td>
+                    <td style={{ padding: '10px' }}>{new Date(request.created_at).toLocaleString()}</td>
+                  </tr>
+                )}</For>
+              </tbody>
+            </table>
+          )}
+        </div>
+      </div>
+    </Layout>
+  );
+};
--- a/client/src/routes/Permissions.tsx
+++ b/client/src/routes/Permissions.tsx
@ -0,0 +1,135 @@
+import { Component, createResource, For, createSignal } from 'solid-js';
+import { api } from '../api/client';
+import type { User, Backend, Permission } from '../types';
+import { Layout } from '../components/Layout';
+
+export const Permissions: Component = () => {
+  const [users, { refetch: refetchUsers }] = createResource(() => api.users.getAll());
+  const [backends, { refetch: refetchBackends }] = createResource(() => api.backends.getAll());
+  const [permissions, { refetch: refetchPermissions }] = createResource(() => api.permissions.getAll());
+  const [showModal, setShowModal] = createSignal(false);
+  const [formData, setFormData] = createSignal({ user_id: '', backend_id: '' });
+
+  const handleSubmit = async (e: Event) => {
+    e.preventDefault();
+    const { user_id, backend_id } = formData();
+    if (!user_id || !backend_id) return;
+
+    await api.permissions.create({ user_id: Number(user_id), backend_id: Number(backend_id) });
+    setFormData({ user_id: '', backend_id: '' });
+    setShowModal(false);
+    refetchPermissions();
+  };
+
+  const handleDelete = async (userId: number, backendId: number) => {
+    if (!confirm('Are you sure you want to revoke this permission?')) return;
+    await api.permissions.delete(userId, backendId);
+    refetchPermissions();
+  };
+
+  return (
+    <Layout>
+      <div style={{ padding: '30px' }}>
+        <div style={{ display: 'flex', 'justify-content': 'space-between', 'align-items': 'center', 'margin-bottom': '20px' }}>
+          <h2 style={{ margin: 0 }}>Permissions</h2>
+          <button
+            onClick={() => setShowModal(true)}
+            style={{ padding: '10px 20px', background: '#3b82f6', color: 'white', border: 'none', 'border-radius': '6px', cursor: 'pointer' }}
+          >
+            Add Permission
+          </button>
+        </div>
+
+        {permissions.loading || users.loading || backends.loading ? (
+          <p>Loading...</p>
+        ) : (
+          <table style={{ width: '100%', 'border-collapse': 'collapse', background: 'white', 'border-radius': '8px', overflow: 'hidden', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
+            <thead style={{ background: '#f8fafc' }}>
+              <tr>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>User</th>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>Backend</th>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>Created At</th>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>Actions</th>
+              </tr>
+            </thead>
+            <tbody>
+              <For each={permissions()}>{(permission) => {
+                const user = users()?.find(u => u.id === permission.user_id);
+                const backend = backends()?.find(b => b.id === permission.backend_id);
+
+                return (
+                  <tr style={{ 'border-bottom': '1px solid #e2e8f0' }}>
+                    <td style={{ padding: '12px' }}>{user?.name || `User #${permission.user_id}`}</td>
+                    <td style={{ padding: '12px' }}>{backend?.name || `Backend #${permission.backend_id}`}</td>
+                    <td style={{ padding: '12px' }}>{new Date(permission.created_at).toLocaleString()}</td>
+                    <td style={{ padding: '12px' }}>
+                      <button
+                        onClick={() => handleDelete(permission.user_id, permission.backend_id)}
+                        style={{ padding: '4px 8px', background: '#ef4444', color: 'white', border: 'none', 'border-radius': '4px', cursor: 'pointer', 'font-size': '0.8rem' }}
+                      >
+                        Revoke
+                      </button>
+                    </td>
+                  </tr>
+                );
+              }}</For>
+            </tbody>
+          </table>
+        )}
+
+        {showModal() && (
+          <div style={{ position: 'fixed', inset: 0, background: 'rgba(0,0,0,0.5)', display: 'flex', 'align-items': 'center', 'justify-content': 'center', 'z-index': 1000 }}>
+            <div style={{ background: 'white', padding: '30px', 'border-radius': '8px', width: '400px' }}>
+              <h3 style={{ margin: '0 0 20px 0' }}>Add Permission</h3>
+              <form onSubmit={handleSubmit}>
+                <div style={{ 'margin-bottom': '15px' }}>
+                  <label style={{ display: 'block', 'margin-bottom': '5px', 'font-weight': 'bold' }}>User *</label>
+                  <select
+                    value={formData().user_id}
+                    onChange={(e) => setFormData({ ...formData(), user_id: e.target.value })}
+                    style={{ width: '100%', padding: '8px', border: '1px solid #cbd5e1', 'border-radius': '4px' }}
+                    required
+                  >
+                    <option value="">Select a user</option>
+                    <For each={users()}>{(user) => (
+                      <option value={user.id}>{user.name}</option>
+                    )}</For>
+                  </select>
+                </div>
+                <div style={{ 'margin-bottom': '20px' }}>
+                  <label style={{ display: 'block', 'margin-bottom': '5px', 'font-weight': 'bold' }}>Backend *</label>
+                  <select
+                    value={formData().backend_id}
+                    onChange={(e) => setFormData({ ...formData(), backend_id: e.target.value })}
+                    style={{ width: '100%', padding: '8px', border: '1px solid #cbd5e1', 'border-radius': '4px' }}
+                    required
+                  >
+                    <option value="">Select a backend</option>
+                    <For each={backends()}>{(backend) => (
+                      <option value={backend.id}>{backend.name}</option>
+                    )}</For>
+                  </select>
+                </div>
+                <div style={{ display: 'flex', gap: '10px', 'justify-content': 'flex-end' }}>
+                  <button
+                    type="button"
+                    onClick={() => setShowModal(false)}
+                    style={{ padding: '8px 16px', background: '#e2e8f0', border: 'none', 'border-radius': '4px', cursor: 'pointer' }}
+                  >
+                    Cancel
+                  </button>
+                  <button
+                    type="submit"
+                    style={{ padding: '8px 16px', background: '#3b82f6', color: 'white', border: 'none', 'border-radius': '4px', cursor: 'pointer' }}
+                  >
+                    Grant
+                  </button>
+                </div>
+              </form>
+            </div>
+          </div>
+        )}
+      </div>
+    </Layout>
+  );
+};
--- a/client/src/routes/Users.tsx
+++ b/client/src/routes/Users.tsx
@ -0,0 +1,136 @@
+import { Component, createResource, For, createSignal } from 'solid-js';
+import { api } from '../api/client';
+import type { User } from '../types';
+import { Layout } from '../components/Layout';
+
+export const Users: Component = () => {
+  const [users, { refetch }] = createResource(() => api.users.getAll());
+  const [showModal, setShowModal] = createSignal(false);
+  const [formData, setFormData] = createSignal({ name: '', email: '' });
+
+  const handleSubmit = async (e: Event) => {
+    e.preventDefault();
+    const { name, email } = formData();
+    if (!name.trim()) return;
+
+    await api.users.create({ name: name.trim(), email: email.trim() || undefined });
+    setFormData({ name: '', email: '' });
+    setShowModal(false);
+    refetch();
+  };
+
+  const handleRegenerateApiKey = async (userId: number) => {
+    await api.users.regenerateApiKey(userId);
+    refetch();
+  };
+
+  const handleDelete = async (userId: number) => {
+    if (!confirm('Are you sure you want to delete this user?')) return;
+    await api.users.delete(userId);
+    refetch();
+  };
+
+  return (
+    <Layout>
+      <div style={{ padding: '30px' }}>
+        <div style={{ display: 'flex', 'justify-content': 'space-between', 'align-items': 'center', 'margin-bottom': '20px' }}>
+          <h2 style={{ margin: 0 }}>Users</h2>
+          <button
+            onClick={() => setShowModal(true)}
+            style={{ padding: '10px 20px', background: '#3b82f6', color: 'white', border: 'none', 'border-radius': '6px', cursor: 'pointer' }}
+          >
+            Add User
+          </button>
+        </div>
+
+        {users.loading ? (
+          <p>Loading...</p>
+        ) : (
+          <table style={{ width: '100%', 'border-collapse': 'collapse', background: 'white', 'border-radius': '8px', overflow: 'hidden', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
+            <thead style={{ background: '#f8fafc' }}>
+              <tr>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>ID</th>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>Name</th>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>Email</th>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>API Key</th>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>Status</th>
+                <th style={{ 'text-align': 'left', padding: '12px', 'border-bottom': '2px solid #e2e8f0' }}>Actions</th>
+              </tr>
+            </thead>
+            <tbody>
+              <For each={users()}>{(user) => (
+                <tr style={{ 'border-bottom': '1px solid #e2e8f0' }}>
+                  <td style={{ padding: '12px' }}>{user.id}</td>
+                  <td style={{ padding: '12px' }}>{user.name}</td>
+                  <td style={{ padding: '12px' }}>{user.email || '-'}</td>
+                  <td style={{ padding: '12px', 'font-family': 'monospace', 'font-size': '0.85rem' }}>{user.api_key.substring(0, 15)}...</td>
+                  <td style={{ padding: '12px', color: user.is_active ? '#22c55e' : '#ef4444' }}>
+                    {user.is_active ? 'Active' : 'Inactive'}
+                  </td>
+                  <td style={{ padding: '12px', display: 'flex', gap: '8px' }}>
+                    <button
+                      onClick={() => handleRegenerateApiKey(user.id)}
+                      style={{ padding: '4px 8px', background: '#64748b', color: 'white', border: 'none', 'border-radius': '4px', cursor: 'pointer', 'font-size': '0.8rem' }}
+                    >
+                      Regenerate Key
+                    </button>
+                    <button
+                      onClick={() => handleDelete(user.id)}
+                      style={{ padding: '4px 8px', background: '#ef4444', color: 'white', border: 'none', 'border-radius': '4px', cursor: 'pointer', 'font-size': '0.8rem' }}
+                    >
+                      Delete
+                    </button>
+                  </td>
+                </tr>
+              )}</For>
+            </tbody>
+          </table>
+        )}
+
+        {showModal() && (
+          <div style={{ position: 'fixed', inset: 0, background: 'rgba(0,0,0,0.5)', display: 'flex', 'align-items': 'center', 'justify-content': 'center', 'z-index': 1000 }}>
+            <div style={{ background: 'white', padding: '30px', 'border-radius': '8px', width: '400px' }}>
+              <h3 style={{ margin: '0 0 20px 0' }}>Add New User</h3>
+              <form onSubmit={handleSubmit}>
+                <div style={{ 'margin-bottom': '15px' }}>
+                  <label style={{ display: 'block', 'margin-bottom': '5px', 'font-weight': 'bold' }}>Name *</label>
+                  <input
+                    type="text"
+                    value={formData().name}
+                    onInput={(e) => setFormData({ ...formData(), name: e.target.value })}
+                    style={{ width: '100%', padding: '8px', border: '1px solid #cbd5e1', 'border-radius': '4px', 'box-sizing': 'border-box' }}
+                    required
+                  />
+                </div>
+                <div style={{ 'margin-bottom': '20px' }}>
+                  <label style={{ display: 'block', 'margin-bottom': '5px', 'font-weight': 'bold' }}>Email</label>
+                  <input
+                    type="email"
+                    value={formData().email}
+                    onInput={(e) => setFormData({ ...formData(), email: e.target.value })}
+                    style={{ width: '100%', padding: '8px', border: '1px solid #cbd5e1', 'border-radius': '4px', 'box-sizing': 'border-box' }}
+                  />
+                </div>
+                <div style={{ display: 'flex', gap: '10px', 'justify-content': 'flex-end' }}>
+                  <button
+                    type="button"
+                    onClick={() => setShowModal(false)}
+                    style={{ padding: '8px 16px', background: '#e2e8f0', border: 'none', 'border-radius': '4px', cursor: 'pointer' }}
+                  >
+                    Cancel
+                  </button>
+                  <button
+                    type="submit"
+                    style={{ padding: '8px 16px', background: '#3b82f6', color: 'white', border: 'none', 'border-radius': '4px', cursor: 'pointer' }}
+                  >
+                    Create
+                  </button>
+                </div>
+              </form>
+            </div>
+          </div>
+        )}
+      </div>
+    </Layout>
+  );
+};
--- a/client/src/types/index.ts
+++ b/client/src/types/index.ts
@ -0,0 +1,62 @@
+export type User = {
+  id: number;
+  api_key: string;
+  name: string;
+  email?: string;
+  is_active: boolean;
+  created_at: string;
+  updated_at: string;
+};
+
+export type Backend = {
+  id: number;
+  name: string;
+  base_url: string;
+  api_key?: string;
+  is_active: boolean;
+  created_at: string;
+  updated_at: string;
+};
+
+export type Permission = {
+  id: number;
+  user_id: number;
+  backend_id: number;
+  created_at: string;
+};
+
+export type RequestLog = {
+  id: number;
+  user_id: number;
+  backend_id: number;
+  endpoint: string;
+  request_model?: string;
+  response_model?: string;
+  prompt_tokens?: number;
+  completion_tokens?: number;
+  total_tokens?: number;
+  status_code: number;
+  response_time_ms?: number;
+  error_message?: string;
+  created_at: string;
+};
+
+export type UsageStats = {
+  id: number;
+  user_id: number;
+  backend_id: number;
+  date: string;
+  total_requests: number;
+  total_tokens: number;
+};
+
+export type BackendMetrics = {
+  id: number;
+  backend_id: number;
+  date: string;
+  total_requests: number;
+  total_tokens: number;
+  avg_response_time_ms: number;
+  error_count: number;
+  success_rate: number;
+};
--- a/client/tsconfig.json
+++ b/client/tsconfig.json
@ -0,0 +1,23 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "ESNext",
+    "lib": ["ES2022", "DOM", "DOM.Iterable"],
+    "jsx": "preserve",
+    "jsxImportSource": "solid-js",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "moduleResolution": "bundler",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "noEmit": true,
+    "baseUrl": ".",
+    "paths": {
+      "~/*": ["src/*"]
+    }
+  },
+  "include": ["src"],
+  "exclude": ["node_modules", "dist"]
+}
--- a/client/vite.config.ts
+++ b/client/vite.config.ts
@ -0,0 +1,19 @@
+import { defineConfig } from 'vite';
+import solidPlugin from 'vite-plugin-solid';
+
+export default defineConfig({
+  plugins: [solidPlugin()],
+  server: {
+    port: 3001,
+    proxy: {
+      '/api': {
+        target: 'http://localhost:3000',
+        changeOrigin: true,
+        rewrite: (path) => path.replace(/^\/api/, ''),
+      },
+    },
+  },
+  build: {
+    target: 'esnext',
+  },
+});
--- a/data/analytics.db
+++ b/data/analytics.db
--- a/data/core.db
+++ b/data/core.db
--- a/database/analytics-schema.sql
+++ b/database/analytics-schema.sql
@ -0,0 +1,58 @@
+-- Analytics Database Schema
+-- Stores request logs, usage stats, and backend metrics
+
+-- Request logs table
+CREATE TABLE IF NOT EXISTS request_logs (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    backend_id INTEGER NOT NULL,
+    endpoint TEXT NOT NULL,
+    request_model TEXT,
+    response_model TEXT,
+    prompt_tokens INTEGER,
+    completion_tokens INTEGER,
+    total_tokens INTEGER,
+    status_code INTEGER,
+    response_time_ms INTEGER,
+    error_message TEXT,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    FOREIGN KEY (user_id) REFERENCES users(id),
+    FOREIGN KEY (backend_id) REFERENCES backends(id)
+);
+
+-- Usage stats table (aggregated daily per user-backend pair)
+CREATE TABLE IF NOT EXISTS usage_stats (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    backend_id INTEGER NOT NULL,
+    date DATE NOT NULL,
+    total_requests INTEGER DEFAULT 0,
+    total_tokens INTEGER DEFAULT 0,
+    FOREIGN KEY (user_id) REFERENCES users(id),
+    FOREIGN KEY (backend_id) REFERENCES backends(id),
+    UNIQUE(user_id, backend_id, date)
+);
+
+-- Backend metrics table (aggregated daily per backend)
+CREATE TABLE IF NOT EXISTS backend_metrics (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    backend_id INTEGER NOT NULL,
+    date DATE NOT NULL,
+    total_requests INTEGER DEFAULT 0,
+    total_tokens INTEGER DEFAULT 0,
+    avg_response_time_ms REAL DEFAULT 0,
+    error_count INTEGER DEFAULT 0,
+    success_rate REAL DEFAULT 1.0,
+    FOREIGN KEY (backend_id) REFERENCES backends(id),
+    UNIQUE(backend_id, date)
+);
+
+-- Indexes for performance
+CREATE INDEX IF NOT EXISTS idx_request_logs_user ON request_logs(user_id);
+CREATE INDEX IF NOT EXISTS idx_request_logs_backend ON request_logs(backend_id);
+CREATE INDEX IF NOT EXISTS idx_request_logs_date ON request_logs(created_at);
+CREATE INDEX IF NOT EXISTS idx_request_logs_user_backend ON request_logs(user_id, backend_id);
+CREATE INDEX IF NOT EXISTS idx_usage_stats_user ON usage_stats(user_id);
+CREATE INDEX IF NOT EXISTS idx_usage_stats_date ON usage_stats(date);
+CREATE INDEX IF NOT EXISTS idx_backend_metrics_backend ON backend_metrics(backend_id);
+CREATE INDEX IF NOT EXISTS idx_backend_metrics_date ON backend_metrics(date);
--- a/database/schema.sql
+++ b/database/schema.sql
@ -0,0 +1,40 @@
+-- Core Database Schema
+-- Stores users, backends, and permissions
+
+-- Users table
+CREATE TABLE IF NOT EXISTS users (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    api_key TEXT UNIQUE NOT NULL,
+    name TEXT NOT NULL,
+    email TEXT,
+    is_active BOOLEAN DEFAULT 1,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+);
+
+-- Backends table
+CREATE TABLE IF NOT EXISTS backends (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    name TEXT UNIQUE NOT NULL,
+    base_url TEXT NOT NULL,
+    api_key TEXT,
+    is_active BOOLEAN DEFAULT 1,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+);
+
+-- Permissions table (many-to-many: users ↔ backends)
+CREATE TABLE IF NOT EXISTS permissions (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    backend_id INTEGER NOT NULL,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
+    FOREIGN KEY (backend_id) REFERENCES backends(id) ON DELETE CASCADE,
+    UNIQUE(user_id, backend_id)
+);
+
+-- Indexes for performance
+CREATE INDEX IF NOT EXISTS idx_users_api_key ON users(api_key);
+CREATE INDEX IF NOT EXISTS idx_permissions_user ON permissions(user_id);
+CREATE INDEX IF NOT EXISTS idx_permissions_backend ON permissions(backend_id);
--- a/docker-compose.yml
+++ b/docker-compose.yml
@ -0,0 +1,25 @@
+version: '3.8'
+
+services:
+  router:
+    build: .
+    ports:
+      - "3000:3000"
+    environment:
+      - NODE_ENV=production
+      - SERVER_PORT=3000
+      - CLIENT_PORT=3001
+      - CORE_DB_PATH=/data/core.db
+      - ANALYTICS_DB_PATH=/data/analytics.db
+      - ADMIN_PASSWORD=${ADMIN_PASSWORD:-}
+    volumes:
+      - router-data:/data
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:3000/health"]
+      interval: 30s
+      timeout: 10s
+      retries: 3
+
+volumes:
+  router-data:
--- a/package.json
+++ b/package.json
@ -0,0 +1,29 @@
+{
+  "name": "kyush-llm-router",
+  "version": "1.0.0",
+  "description": "LLM routing server with multi-user API key management",
+  "scripts": {
+    "dev": "concurrently \"pnpm exec tsx watch server/src/index.ts\" \"pnpm -r --filter client run dev\"",
+    "build": "pnpm -r build",
+    "start": "pnpm -r start"
+  },
+  "keywords": [
+    "llm",
+    "router",
+    "openai",
+    "proxy"
+  ],
+  "author": "",
+  "license": "MIT",
+  "workspaces": [
+    "server",
+    "client"
+  ],
+  "engines": {
+    "node": ">=18.0.0"
+  },
+  "devDependencies": {
+    "concurrently": "^9.2.1",
+    "tsx": "^4.21.0"
+  }
+}
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
--- a/pnpm-workspace.yaml
+++ b/pnpm-workspace.yaml
@ -0,0 +1,7 @@
+packages:
+  - 'server'
+  - 'client'
+
+onlyBuiltDependencies:
+  - 'better-sqlite3'
+  - 'esbuild'
--- a/scripts/dev.js
+++ b/scripts/dev.js
@ -0,0 +1,92 @@
+#!/usr/bin/env node
+
+const { spawn } = require('child_process');
+const path = require('path');
+
+const colors = {
+  reset: '\x1b[0m',
+  red: '\x1b[31m',
+  green: '\x1b[32m',
+  yellow: '\x1b[33m',
+  blue: '\x1b[34m',
+  cyan: '\x1b[36m',
+};
+
+function log(color, message) {
+  console.log(`${color}${message}${colors.reset}`);
+}
+
+function runCommand(name, cwd, args) {
+  return new Promise((resolve, reject) => {
+    const proc = spawn(args[0], args.slice(1), {
+      cwd,
+      stdio: 'inherit',
+      shell: true,
+    });
+
+    proc.on('error', (err) => {
+      log(colors.red, `[${name}] Failed to start: ${err.message}`);
+      reject(err);
+    });
+
+    proc.on('close', (code) => {
+      if (code !== 0) {
+        log(colors.red, `[${name}] Process exited with code ${code}`);
+        reject(new Error(`${name} exited with code ${code}`));
+      } else {
+        resolve();
+      }
+    });
+  });
+}
+
+async function main() {
+  log(colors.cyan, 'Starting Kyush LLM Router development environment...');
+  log(colors.cyan, '===============================================');
+
+  const serverDir = path.join(__dirname, '..', 'server');
+  const clientDir = path.join(__dirname, '..', 'client');
+
+  const serverProcess = spawn('npm', ['run', 'dev'], {
+    cwd: serverDir,
+    stdio: 'inherit',
+    shell: true,
+  });
+
+  const clientProcess = spawn('npm', ['run', 'dev'], {
+    cwd: clientDir,
+    stdio: 'inherit',
+    shell: true,
+  });
+
+  log(colors.green, '===============================================');
+  log(colors.green, 'Development servers started:');
+  log(colors.green, `  - Express API Server: http://localhost:3000`);
+  log(colors.green, `  - Vite Admin Dashboard: http://localhost:3001`);
+  log(colors.green, '===============================================');
+  log(colors.yellow, 'Press Ctrl+C to stop all servers');
+
+  process.on('SIGINT', () => {
+    log(colors.yellow, '\nShutting down...');
+    serverProcess.kill('SIGINT');
+    clientProcess.kill('SIGINT');
+    process.exit(0);
+  });
+
+  process.on('SIGTERM', () => {
+    log(colors.yellow, '\nShutting down...');
+    serverProcess.kill('SIGTERM');
+    clientProcess.kill('SIGTERM');
+    process.exit(0);
+  });
+
+  await Promise.all([
+    new Promise((_, reject) => serverProcess.on('error', reject)),
+    new Promise((_, reject) => clientProcess.on('error', reject)),
+  ]);
+}
+
+main().catch((err) => {
+  log(colors.red, `Fatal error: ${err.message}`);
+  process.exit(1);
+});
--- a/server/package.json
+++ b/server/package.json
@ -0,0 +1,31 @@
+{
+  "name": "server",
+  "version": "1.0.0",
+  "description": "LLM Router Server",
+  "main": "dist/index.js",
+  "scripts": {
+    "build": "tsc",
+    "start": "node dist/index.js",
+    "dev": "tsx watch src/index.ts",
+    "typecheck": "tsc --noEmit"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "MIT",
+  "dependencies": {
+    "better-sqlite3": "^12.6.2",
+    "cors": "^2.8.6",
+    "dotenv": "^17.3.1",
+    "express": "^5.2.1",
+    "node-fetch": "^3.3.2",
+    "zod": "^4.3.6"
+  },
+  "devDependencies": {
+    "@types/better-sqlite3": "^7.6.13",
+    "@types/cors": "^2.8.19",
+    "@types/express": "^5.0.6",
+    "@types/node": "^25.3.3",
+    "tsx": "^4.21.0",
+    "typescript": "^5.9.3"
+  }
+}
--- a/server/src/config/analytics-db.ts
+++ b/server/src/config/analytics-db.ts
@ -0,0 +1,23 @@
+import Database from 'better-sqlite3';
+import path from 'path';
+import fs from 'fs';
+
+const ANALYTICS_DB_PATH = process.env.ANALYTICS_DB_PATH || path.join(process.cwd(), 'data', 'analytics.db');
+
+// Ensure data directory exists
+const dataDir = path.dirname(ANALYTICS_DB_PATH);
+if (!fs.existsSync(dataDir)) {
+  fs.mkdirSync(dataDir, { recursive: true });
+}
+
+const db = new Database(ANALYTICS_DB_PATH);
+
+// Enable foreign keys
+db.pragma('foreign_keys = ON');
+
+// Initialize schema
+const schemaPath = path.join(__dirname, '..', '..', '..', 'database', 'analytics-schema.sql');
+const schema = fs.readFileSync(schemaPath, 'utf-8');
+db.exec(schema);
+
+export default db;
--- a/server/src/config/database.ts
+++ b/server/src/config/database.ts
@ -0,0 +1,23 @@
+import Database from 'better-sqlite3';
+import path from 'path';
+import fs from 'fs';
+
+const CORE_DB_PATH = process.env.CORE_DB_PATH || path.join(process.cwd(), 'data', 'core.db');
+
+// Ensure data directory exists
+const dataDir = path.dirname(CORE_DB_PATH);
+if (!fs.existsSync(dataDir)) {
+  fs.mkdirSync(dataDir, { recursive: true });
+}
+
+const db = new Database(CORE_DB_PATH);
+
+// Enable foreign keys
+db.pragma('foreign_keys = ON');
+
+// Initialize schema
+const schemaPath = path.join(__dirname, '..', '..', '..', 'database', 'schema.sql');
+const schema = fs.readFileSync(schemaPath, 'utf-8');
+db.exec(schema);
+
+export default db;
--- a/server/src/index.ts
+++ b/server/src/index.ts
@ -0,0 +1,38 @@
+import express from 'express';
+import cors from 'cors';
+import dotenv from 'dotenv';
+import path from 'path';
+
+import adminRoutes from './routes/admin';
+import apiRoutes from './routes/api';
+import analyticsRoutes from './routes/analytics';
+import { logger } from './utils/logger';
+
+dotenv.config();
+
+const app = express();
+const PORT = process.env.SERVER_PORT || 3000;
+
+app.use(cors({
+  origin: ['http://localhost:5173', 'http://localhost:3001'],
+  credentials: true,
+}));
+app.use(express.json());
+
+app.use('/admin', adminRoutes);
+app.use('/v1', apiRoutes);
+app.use('/admin/analytics', analyticsRoutes);
+
+app.get('/health', (req, res) => {
+  res.json({ status: 'ok', timestamp: new Date().toISOString() });
+});
+
+app.use((req, res) => {
+  res.status(404).json({ error: 'Not found' });
+});
+
+app.listen(PORT, () => {
+  logger.info(`Server running on port ${PORT}`);
+  logger.info(`Admin API: http://localhost:${PORT}/admin`);
+  logger.info(`OpenAI API: http://localhost:${PORT}/v1`);
+});
--- a/server/src/models/Backend.ts
+++ b/server/src/models/Backend.ts
@ -0,0 +1,75 @@
+import db from '../config/database';
+import { Backend, CreateBackendData, UpdateBackendData } from '../../../shared/types';
+
+export class BackendModel {
+  static findAll(): Backend[] {
+    return db.prepare('SELECT * FROM backends ORDER BY created_at DESC').all() as Backend[];
+  }
+
+  static findById(id: number): Backend | undefined {
+    return db.prepare('SELECT * FROM backends WHERE id = ?').get(id) as Backend | undefined;
+  }
+
+  static findActive(): Backend[] {
+    return db.prepare('SELECT * FROM backends WHERE is_active = 1 ORDER BY name').all() as Backend[];
+  }
+
+  static create(data: CreateBackendData): Backend {
+    const stmt = db.prepare(
+      'INSERT INTO backends (name, base_url, api_key) VALUES (?, ?, ?)'
+    );
+    const result = stmt.run(data.name, data.base_url, data.api_key || null);
+
+    return {
+      id: result.lastInsertRowid as number,
+      name: data.name,
+      base_url: data.base_url,
+      api_key: data.api_key,
+      is_active: true,
+      created_at: new Date().toISOString(),
+      updated_at: new Date().toISOString(),
+    };
+  }
+
+  static update(id: number, data: UpdateBackendData): Backend | undefined {
+    const updates: string[] = [];
+    const values: unknown[] = [];
+
+    if (data.name !== undefined) {
+      updates.push('name = ?');
+      values.push(data.name);
+    }
+    if (data.base_url !== undefined) {
+      updates.push('base_url = ?');
+      values.push(data.base_url);
+    }
+    if (data.api_key !== undefined) {
+      updates.push('api_key = ?');
+      values.push(data.api_key);
+    }
+    if (data.is_active !== undefined) {
+      updates.push('is_active = ?');
+      values.push(data.is_active);
+    }
+
+    if (updates.length === 0) {
+      return this.findById(id);
+    }
+
+    updates.push('updated_at = CURRENT_TIMESTAMP');
+    values.push(id);
+
+    db.prepare(`UPDATE backends SET ${updates.join(', ')} WHERE id = ?`).run(...values);
+    return this.findById(id);
+  }
+
+  static delete(id: number): boolean {
+    const result = db.prepare('DELETE FROM backends WHERE id = ?').run(id);
+    return result.changes > 0;
+  }
+
+  static deactivate(id: number): boolean {
+    const result = db.prepare('UPDATE backends SET is_active = 0, updated_at = CURRENT_TIMESTAMP WHERE id = ?').run(id);
+    return result.changes > 0;
+  }
+}
--- a/server/src/models/Permission.ts
+++ b/server/src/models/Permission.ts
@ -0,0 +1,61 @@
+import db from '../config/database';
+import { Permission, CreatePermissionData } from '../../../shared/types';
+
+export class PermissionModel {
+  static findAll(): Permission[] {
+    return db.prepare('SELECT * FROM permissions ORDER BY created_at DESC').all() as Permission[];
+  }
+
+  static findByUserId(userId: number): Permission[] {
+    return db.prepare('SELECT * FROM permissions WHERE user_id = ? ORDER BY backend_id').all(userId) as Permission[];
+  }
+
+  static findByBackendId(backendId: number): Permission[] {
+    return db.prepare('SELECT * FROM permissions WHERE backend_id = ? ORDER BY user_id').all(backendId) as Permission[];
+  }
+
+  static findUserBackendPermissions(userId: number, backendId: number): Permission | undefined {
+    return db.prepare('SELECT * FROM permissions WHERE user_id = ? AND backend_id = ?').get(userId, backendId) as Permission | undefined;
+  }
+
+  static create(data: CreatePermissionData): Permission {
+    try {
+      const stmt = db.prepare(
+        'INSERT INTO permissions (user_id, backend_id) VALUES (?, ?)'
+      );
+      const result = stmt.run(data.user_id, data.backend_id);
+
+      return {
+        id: result.lastInsertRowid as number,
+        user_id: data.user_id,
+        backend_id: data.backend_id,
+        created_at: new Date().toISOString(),
+      };
+    } catch (error) {
+      if (error instanceof Error && error.message.includes('UNIQUE constraint failed')) {
+        throw new Error('Permission already exists for this user and backend');
+      }
+      throw error;
+    }
+  }
+
+  static delete(user_id: number, backend_id: number): boolean {
+    const result = db.prepare('DELETE FROM permissions WHERE user_id = ? AND backend_id = ?').run(user_id, backend_id);
+    return result.changes > 0;
+  }
+
+  static deleteByUserId(userId: number): number {
+    const result = db.prepare('DELETE FROM permissions WHERE user_id = ?').run(userId);
+    return result.changes;
+  }
+
+  static deleteByBackendId(backendId: number): number {
+    const result = db.prepare('DELETE FROM permissions WHERE backend_id = ?').run(backendId);
+    return result.changes;
+  }
+
+  static getUserBackendIds(userId: number): number[] {
+    const rows = db.prepare('SELECT backend_id FROM permissions WHERE user_id = ?').all(userId) as { backend_id: number }[];
+    return rows.map(row => row.backend_id);
+  }
+}
--- a/server/src/models/User.ts
+++ b/server/src/models/User.ts
@ -0,0 +1,80 @@
+import db from '../config/database';
+import { User, CreateUserData, UpdateUserData } from '../../../shared/types';
+
+export class UserModel {
+  static findAll(): User[] {
+    return db.prepare('SELECT * FROM users ORDER BY created_at DESC').all() as User[];
+  }
+
+  static findById(id: number): User | undefined {
+    return db.prepare('SELECT * FROM users WHERE id = ?').get(id) as User | undefined;
+  }
+
+  static findByApiKey(apiKey: string): User | undefined {
+    return db.prepare('SELECT * FROM users WHERE api_key = ? AND is_active = 1').get(apiKey) as User | undefined;
+  }
+
+  static create(data: CreateUserData): User {
+    const stmt = db.prepare(
+      'INSERT INTO users (api_key, name, email) VALUES (?, ?, ?)'
+    );
+    const result = stmt.run(data.name, data.email || null);
+    
+    return {
+      id: result.lastInsertRowid as number,
+      api_key: data.name,
+      name: data.name,
+      email: data.email,
+      is_active: true,
+      created_at: new Date().toISOString(),
+      updated_at: new Date().toISOString(),
+    };
+  }
+
+  static update(id: number, data: UpdateUserData): User | undefined {
+    const updates: string[] = [];
+    const values: unknown[] = [];
+
+    if (data.name !== undefined) {
+      updates.push('name = ?');
+      values.push(data.name);
+    }
+    if (data.email !== undefined) {
+      updates.push('email = ?');
+      values.push(data.email);
+    }
+    if (data.is_active !== undefined) {
+      updates.push('is_active = ?');
+      values.push(data.is_active);
+    }
+
+    if (updates.length === 0) {
+      return this.findById(id);
+    }
+
+    updates.push('updated_at = CURRENT_TIMESTAMP');
+    values.push(id);
+
+    db.prepare(`UPDATE users SET ${updates.join(', ')} WHERE id = ?`).run(...values);
+    return this.findById(id);
+  }
+
+  static delete(id: number): boolean {
+    const result = db.prepare('DELETE FROM users WHERE id = ?').run(id);
+    return result.changes > 0;
+  }
+
+  static deactivate(id: number): boolean {
+    const result = db.prepare('UPDATE users SET is_active = 0, updated_at = CURRENT_TIMESTAMP WHERE id = ?').run(id);
+    return result.changes > 0;
+  }
+
+  static regenerateApiKey(id: number): string | null {
+    const user = this.findById(id);
+    if (!user) return null;
+
+    const newApiKey = `sk-${Date.now()}-${Math.random().toString(36).substring(2, 15)}`;
+    db.prepare('UPDATE users SET api_key = ?, updated_at = CURRENT_TIMESTAMP WHERE id = ?').run(newApiKey, id);
+    return newApiKey;
+  }
+}
--- a/server/src/routes/admin.ts
+++ b/server/src/routes/admin.ts
@ -0,0 +1,216 @@
+import { Router, Request, Response } from 'express';
+import { UserModel } from '../models/User';
+import { BackendModel } from '../models/Backend';
+import { PermissionModel } from '../models/Permission';
+import { generateApiKey } from '../utils/apiKey';
+import { CreateUserData, CreateBackendData, CreatePermissionData, UpdateUserData, UpdateBackendData } from '../../../shared/types';
+
+const router = Router();
+
+// ============ User Management ============
+
+router.get('/users', (req: Request, res: Response) => {
+  const users = UserModel.findAll();
+  res.json(users);
+});
+
+router.post('/users', (req: Request, res: Response) => {
+  const { name, email } = req.body as CreateUserData;
+
+  if (!name) {
+    res.status(400).json({ error: 'Name is required' });
+    return;
+  }
+
+  const user = UserModel.create({
+    name,
+    email,
+  });
+
+  const updatedUser = UserModel.regenerateApiKey(user.id);
+  if (updatedUser) {
+    user.api_key = updatedUser;
+  }
+
+  res.status(201).json(user);
+});
+
+router.get('/users/:id', (req: Request, res: Response) => {
+  const id = Number(req.params.id);
+  const user = UserModel.findById(id);
+
+  if (!user) {
+    res.status(404).json({ error: 'User not found' });
+    return;
+  }
+
+  res.json(user);
+});
+
+router.put('/users/:id', (req: Request, res: Response) => {
+  const id = Number(req.params.id);
+  const user = UserModel.findById(id);
+
+  if (!user) {
+    res.status(404).json({ error: 'User not found' });
+    return;
+  }
+
+  const { name, email, is_active } = req.body as UpdateUserData;
+  const updatedUser = UserModel.update(id, { name, email, is_active });
+
+  res.json(updatedUser);
+});
+
+router.delete('/users/:id', (req: Request, res: Response) => {
+  const id = Number(req.params.id);
+  const success = UserModel.delete(id);
+
+  if (!success) {
+    res.status(404).json({ error: 'User not found' });
+    return;
+  }
+
+  res.status(204).send();
+});
+
+router.post('/users/:id/regenerate-api-key', (req: Request, res: Response) => {
+  const id = Number(req.params.id);
+  const user = UserModel.findById(id);
+
+  if (!user) {
+    res.status(404).json({ error: 'User not found' });
+    return;
+  }
+
+  const newApiKey = UserModel.regenerateApiKey(id);
+  if (!newApiKey) {
+    res.status(500).json({ error: 'Failed to regenerate API key' });
+    return;
+  }
+
+  res.json({ ...user, api_key: newApiKey });
+});
+
+// ============ Backend Management ============
+
+router.get('/backends', (req: Request, res: Response) => {
+  const backends = BackendModel.findAll();
+  res.json(backends);
+});
+
+router.post('/backends', (req: Request, res: Response) => {
+  const { name, base_url, api_key } = req.body as CreateBackendData;
+
+  if (!name || !base_url) {
+    res.status(400).json({ error: 'Name and base_url are required' });
+    return;
+  }
+
+  const backend = BackendModel.create({ name, base_url, api_key });
+  res.status(201).json(backend);
+});
+
+router.get('/backends/:id', (req: Request, res: Response) => {
+  const id = Number(req.params.id);
+  const backend = BackendModel.findById(id);
+
+  if (!backend) {
+    res.status(404).json({ error: 'Backend not found' });
+    return;
+  }
+
+  res.json(backend);
+});
+
+router.put('/backends/:id', (req: Request, res: Response) => {
+  const id = Number(req.params.id);
+  const backend = BackendModel.findById(id);
+
+  if (!backend) {
+    res.status(404).json({ error: 'Backend not found' });
+    return;
+  }
+
+  const { name, base_url, api_key, is_active } = req.body as UpdateBackendData;
+  const updatedBackend = BackendModel.update(id, { name, base_url, api_key, is_active });
+
+  res.json(updatedBackend);
+});
+
+router.delete('/backends/:id', (req: Request, res: Response) => {
+  const id = Number(req.params.id);
+  const success = BackendModel.delete(id);
+
+  if (!success) {
+    res.status(404).json({ error: 'Backend not found' });
+    return;
+  }
+
+  res.status(204).send();
+});
+
+// ============ Permission Management ============
+
+router.get('/permissions', (req: Request, res: Response) => {
+  const permissions = PermissionModel.findAll();
+  res.json(permissions);
+});
+
+router.get('/permissions/user/:userId', (req: Request, res: Response) => {
+  const userId = Number(req.params.userId);
+  const permissions = PermissionModel.findByUserId(userId);
+  res.json(permissions);
+});
+
+router.get('/permissions/backend/:backendId', (req: Request, res: Response) => {
+  const backendId = Number(req.params.backendId);
+  const permissions = PermissionModel.findByBackendId(backendId);
+  res.json(permissions);
+});
+
+router.post('/permissions', (req: Request, res: Response) => {
+  const { user_id, backend_id } = req.body as CreatePermissionData;
+
+  if (!user_id || !backend_id) {
+    res.status(400).json({ error: 'user_id and backend_id are required' });
+    return;
+  }
+
+  try {
+    const permission = PermissionModel.create({ user_id, backend_id });
+    res.status(201).json(permission);
+  } catch (error) {
+    if (error instanceof Error && error.message.includes('already exists')) {
+      res.status(409).json({ error: error.message });
+      return;
+    }
+    res.status(500).json({ error: 'Failed to create permission' });
+  }
+});
+
+router.delete('/permissions', (req: Request, res: Response) => {
+  const { user_id, backend_id } = req.query as { user_id?: string; backend_id?: string };
+
+  if (!user_id || !backend_id) {
+    res.status(400).json({ error: 'user_id and backend_id are required' });
+    return;
+  }
+
+  const success = PermissionModel.delete(Number(user_id), Number(backend_id));
+
+  if (!success) {
+    res.status(404).json({ error: 'Permission not found' });
+    return;
+  }
+
+  res.status(204).send();
+});
+
+// ============ Health Check ============
+
+router.get('/health', (req: Request, res: Response) => {
+  res.json({ status: 'ok', timestamp: new Date().toISOString() });
+});
+
+export default router;
--- a/server/src/routes/analytics.ts
+++ b/server/src/routes/analytics.ts
@ -0,0 +1,34 @@
+import { Router, Request, Response } from 'express';
+import { AnalyticsService } from '../services/AnalyticsService';
+
+const router = Router();
+
+router.get('/usage', (req: Request, res: Response) => {
+  const { userId, backendId, days } = req.query;
+  const result = AnalyticsService.getUsageStats(
+    userId ? Number(userId) : undefined,
+    backendId ? Number(backendId) : undefined,
+    days ? Number(days) : 30
+  );
+  res.json(result);
+});
+
+router.get('/requests', (req: Request, res: Response) => {
+  const { limit, offset } = req.query;
+  const result = AnalyticsService.getRequestLogs(
+    limit ? Number(limit) : 100,
+    offset ? Number(offset) : 0
+  );
+  res.json(result);
+});
+
+router.get('/metrics', (req: Request, res: Response) => {
+  const { backendId, days } = req.query;
+  const result = AnalyticsService.getBackendMetrics(
+    backendId ? Number(backendId) : undefined,
+    days ? Number(days) : 30
+  );
+  res.json(result);
+});
+
+export default router;
--- a/server/src/routes/api.ts
+++ b/server/src/routes/api.ts
@ -0,0 +1,106 @@
+import { Router, Request, Response } from 'express';
+import { authenticate, AuthenticatedRequest } from './auth';
+import { RouterService } from '../services/RouterService';
+import { AnalyticsService } from '../services/AnalyticsService';
+import { logger } from '../utils/logger';
+
+const router = Router();
+
+router.use(authenticate);
+
+router.post('/chat/completions', async (req: AuthenticatedRequest, res: Response) => {
+  const startTime = Date.now();
+  const user = req.user!;
+  const allowedBackendIds = req.allowedBackendIds!;
+
+  if (allowedBackendIds.length === 0) {
+    res.status(403).json({ error: 'No backends available for your account' });
+    return;
+  }
+
+  const backend = RouterService.selectBackend(allowedBackendIds);
+  if (!backend) {
+    res.status(403).json({ error: 'No active backends available' });
+    return;
+  }
+
+  try {
+    const { model, messages, ...rest } = req.body;
+
+    const response = await RouterService.forwardRequest(
+      backend,
+      '/v1/chat/completions',
+      'POST',
+      { 'Content-Type': 'application/json' },
+      req.body
+    );
+
+    const responseTime = Date.now() - startTime;
+
+    AnalyticsService.logRequest({
+      user_id: user.id,
+      backend_id: backend.id,
+      endpoint: '/v1/chat/completions',
+      request_model: model,
+      response_model: response.data && typeof response.data === 'object' && 'model' in response.data ? String(response.data.model) : undefined,
+      prompt_tokens: response.data && typeof response.data === 'object' && 'usage' in response.data && typeof (response.data as { usage?: { prompt_tokens?: number } }).usage === 'object' ? (response.data as { usage: { prompt_tokens: number } }).usage?.prompt_tokens : undefined,
+      completion_tokens: response.data && typeof response.data === 'object' && 'usage' in response.data && typeof (response.data as { usage?: { completion_tokens?: number } }).usage === 'object' ? (response.data as { usage: { completion_tokens: number } }).usage?.completion_tokens : undefined,
+      total_tokens: response.data && typeof response.data === 'object' && 'usage' in response.data && typeof (response.data as { usage?: { total_tokens?: number } }).usage === 'object' ? (response.data as { usage: { total_tokens: number } }).usage?.total_tokens : undefined,
+      status_code: response.status,
+      response_time_ms: responseTime,
+      error_message: response.status >= 400 ? JSON.stringify(response.data) : undefined,
+    });
+
+    if (response.status >= 400) {
+      logger.error(`Backend error for user ${user.id}: ${JSON.stringify(response.data)}`);
+    }
+
+    res.status(response.status).json(response.data);
+  } catch (error) {
+    const responseTime = Date.now() - startTime;
+
+    AnalyticsService.logRequest({
+      user_id: user.id,
+      backend_id: backend.id,
+      endpoint: '/v1/chat/completions',
+      request_model: req.body.model,
+      status_code: 502,
+      response_time_ms: responseTime,
+      error_message: error instanceof Error ? error.message : 'Unknown error',
+    });
+
+    logger.error(`Request failed for user ${user.id}: ${error instanceof Error ? error.message : 'Unknown error'}`);
+    res.status(502).json({ error: 'Backend request failed' });
+  }
+});
+
+router.get('/models', async (req: AuthenticatedRequest, res: Response) => {
+  const allowedBackendIds = req.allowedBackendIds!;
+
+  if (allowedBackendIds.length === 0) {
+    res.status(403).json({ error: 'No backends available for your account' });
+    return;
+  }
+
+  const backend = RouterService.selectBackend(allowedBackendIds);
+  if (!backend) {
+    res.status(403).json({ error: 'No active backends available' });
+    return;
+  }
+
+  try {
+    const response = await RouterService.forwardRequest(
+      backend,
+      '/v1/models',
+      'GET',
+      {}
+    );
+
+    res.status(response.status).json(response.data);
+  } catch (error) {
+    logger.error(`Models request failed for user ${req.user!.id}: ${error instanceof Error ? error.message : 'Unknown error'}`);
+    res.status(502).json({ error: 'Failed to fetch models from backend' });
+  }
+});
+
+export default router;
--- a/server/src/routes/auth.ts
+++ b/server/src/routes/auth.ts
@ -0,0 +1,48 @@
+import { Request, Response, NextFunction } from 'express';
+import { UserModel } from '../models/User';
+import { PermissionModel } from '../models/Permission';
+import { User } from '../../../shared/types';
+
+export interface AuthenticatedRequest extends Request {
+  user?: User;
+  allowedBackendIds?: number[];
+}
+
+export function authenticate(req: AuthenticatedRequest, res: Response, next: NextFunction): void {
+  const authHeader = req.headers.authorization;
+
+  if (!authHeader || !authHeader.startsWith('Bearer ')) {
+    res.status(401).json({ error: 'Missing or invalid authorization header' });
+    return;
+  }
+
+  const apiKey = authHeader.substring(7);
+  const user = UserModel.findByApiKey(apiKey);
+
+  if (!user) {
+    res.status(401).json({ error: 'Invalid API key' });
+    return;
+  }
+
+  req.user = user;
+  req.allowedBackendIds = PermissionModel.getUserBackendIds(user.id);
+  next();
+}
+
+export function requireBackendPermission(backendId?: number) {
+  return (req: AuthenticatedRequest, res: Response, next: NextFunction): void => {
+    if (!req.user) {
+      res.status(401).json({ error: 'Authentication required' });
+      return;
+    }
+
+    const targetBackendId = backendId || Number(req.params.backendId);
+
+    if (!req.allowedBackendIds?.includes(targetBackendId)) {
+      res.status(403).json({ error: 'Access denied to this backend' });
+      return;
+    }
+
+    next();
+  };
+}
--- a/server/src/services/AnalyticsService.ts
+++ b/server/src/services/AnalyticsService.ts
@ -0,0 +1,144 @@
+import analyticsDb from '../config/analytics-db';
+import { RequestLog } from '../../../shared/types';
+
+export class AnalyticsService {
+  static logRequest(logData: Omit<RequestLog, 'id' | 'created_at'>): void {
+    const stmt = analyticsDb.prepare(`
+      INSERT INTO request_logs (
+        user_id, backend_id, endpoint, request_model, response_model,
+        prompt_tokens, completion_tokens, total_tokens,
+        status_code, response_time_ms, error_message
+      ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+    `);
+
+    stmt.run(
+      logData.user_id,
+      logData.backend_id,
+      logData.endpoint,
+      logData.request_model || null,
+      logData.response_model || null,
+      logData.prompt_tokens || null,
+      logData.completion_tokens || null,
+      logData.total_tokens || null,
+      logData.status_code,
+      logData.response_time_ms || null,
+      logData.error_message || null
+    );
+
+    this.updateUsageStats(logData.user_id, logData.backend_id, logData.total_tokens || 0);
+    this.updateBackendMetrics(logData.backend_id, logData);
+  }
+
+  private static updateUsageStats(userId: number, backendId: number, tokens: number): void {
+    const today = new Date().toISOString().split('T')[0];
+
+    const upsertStmt = analyticsDb.prepare(`
+      INSERT INTO usage_stats (user_id, backend_id, date, total_requests, total_tokens)
+      VALUES (?, ?, ?, 1, ?)
+      ON CONFLICT(user_id, backend_id, date)
+      DO UPDATE SET
+        total_requests = total_requests + 1,
+        total_tokens = total_tokens + ?
+    `);
+
+    upsertStmt.run(userId, backendId, today, tokens, tokens);
+  }
+
+  private static updateBackendMetrics(backendId: number, logData: Omit<RequestLog, 'id' | 'created_at'>): void {
+    const today = new Date().toISOString().split('T')[0];
+    const isSuccess = logData.status_code >= 200 && logData.status_code < 300;
+
+    const existing = analyticsDb.prepare(
+      'SELECT * FROM backend_metrics WHERE backend_id = ? AND date = ?'
+    ).get(backendId, today) as {
+      total_requests: number;
+      total_tokens: number;
+      avg_response_time_ms: number;
+      error_count: number;
+    } | undefined;
+
+    if (existing) {
+      const newTotalRequests = existing.total_requests + 1;
+      const newTotalTokens = existing.total_tokens + (logData.total_tokens || 0);
+      const newErrorCount = existing.error_count + (isSuccess ? 0 : 1);
+      const newAvgResponseTime = logData.response_time_ms
+        ? (existing.avg_response_time_ms * existing.total_requests + logData.response_time_ms) / newTotalRequests
+        : existing.avg_response_time_ms;
+      const newSuccessRate = (newTotalRequests - newErrorCount) / newTotalRequests;
+
+      analyticsDb.prepare(`
+        UPDATE backend_metrics SET
+          total_requests = ?,
+          total_tokens = ?,
+          avg_response_time_ms = ?,
+          error_count = ?,
+          success_rate = ?
+        WHERE backend_id = ? AND date = ?
+      `).run(newTotalRequests, newTotalTokens, newAvgResponseTime, newErrorCount, newSuccessRate, backendId, today);
+    } else {
+      analyticsDb.prepare(`
+        INSERT INTO backend_metrics (
+          backend_id, date, total_requests, total_tokens,
+          avg_response_time_ms, error_count, success_rate
+        ) VALUES (?, ?, 1, ?, ?, ?, ?)
+      `).run(
+        backendId,
+        today,
+        logData.total_tokens || 0,
+        logData.response_time_ms || 0,
+        isSuccess ? 0 : 1,
+        isSuccess ? 1.0 : 0.0
+      );
+    }
+  }
+
+  static getRequestLogs(limit: number = 100, offset: number = 0): RequestLog[] {
+    return analyticsDb.prepare(`
+      SELECT * FROM request_logs ORDER BY created_at DESC LIMIT ? OFFSET ?
+    `).all(limit, offset) as RequestLog[];
+  }
+
+  static getUsageStats(userId?: number, backendId?: number, days: number = 30): unknown[] {
+    const endDate = new Date().toISOString().split('T')[0];
+    const startDate = new Date(Date.now() - days * 24 * 60 * 60 * 1000).toISOString().split('T')[0];
+
+    let query = `
+      SELECT * FROM usage_stats 
+      WHERE date >= ? AND date <= ?
+    `;
+    const params: unknown[] = [startDate, endDate];
+
+    if (userId) {
+      query += ' AND user_id = ?';
+      params.push(userId);
+    }
+    if (backendId) {
+      query += ' AND backend_id = ?';
+      params.push(backendId);
+    }
+
+    query += ' ORDER BY date DESC, user_id, backend_id';
+
+    return analyticsDb.prepare(query).all(...params);
+  }
+
+  static getBackendMetrics(backendId?: number, days: number = 30): unknown[] {
+    const endDate = new Date().toISOString().split('T')[0];
+    const startDate = new Date(Date.now() - days * 24 * 60 * 60 * 1000).toISOString().split('T')[0];
+
+    let query = `
+      SELECT * FROM backend_metrics 
+      WHERE date >= ? AND date <= ?
+    `;
+    const params: unknown[] = [startDate, endDate];
+
+    if (backendId) {
+      query += ' AND backend_id = ?';
+      params.push(backendId);
+    }
+
+    query += ' ORDER BY date DESC';
+
+    return analyticsDb.prepare(query).all(...params);
+  }
+}
--- a/server/src/services/RouterService.ts
+++ b/server/src/services/RouterService.ts
@ -0,0 +1,59 @@
+import { Backend } from '../../../shared/types';
+import { BackendModel } from '../models/Backend';
+
+export class RouterService {
+  static selectBackend(allowedBackendIds: number[]): Backend | null {
+    if (allowedBackendIds.length === 0) {
+      return null;
+    }
+
+    const backends = BackendModel.findAll()
+      .filter(b => b.is_active && allowedBackendIds.includes(b.id));
+
+    if (backends.length === 0) {
+      return null;
+    }
+
+    const roundRobinIndex = Math.floor(Math.random() * backends.length);
+    return backends[roundRobinIndex];
+  }
+
+  static async forwardRequest(
+    backend: Backend,
+    path: string,
+    method: string,
+    headers: Record<string, string>,
+    body?: unknown
+  ): Promise<{ status: number; data: unknown }> {
+    const backendUrl = backend.base_url.replace(/\/$/, '') + path;
+
+    const fetchHeaders: Record<string, string> = {
+      'Content-Type': 'application/json',
+      ...headers,
+    };
+
+    if (backend.api_key) {
+      fetchHeaders['Authorization'] = `Bearer ${backend.api_key}`;
+    }
+
+    try {
+      const response = await fetch(backendUrl, {
+        method,
+        headers: fetchHeaders,
+        body: body ? JSON.stringify(body) : undefined,
+      });
+
+      const data = await response.json().catch(() => ({}));
+
+      return {
+        status: response.status,
+        data,
+      };
+    } catch (error) {
+      return {
+        status: 502,
+        data: { error: 'Failed to forward request to backend' },
+      };
+    }
+  }
+}
--- a/server/src/utils/apiKey.ts
+++ b/server/src/utils/apiKey.ts
@ -0,0 +1,9 @@
+export function generateApiKey(): string {
+  const timestamp = Date.now().toString(36);
+  const random = Math.random().toString(36).substring(2, 15);
+  return `sk-${timestamp}-${random}`;
+}
+
+export function isValidApiKey(key: string): boolean {
+  return key.startsWith('sk-') && key.length > 10;
+}
--- a/server/src/utils/logger.ts
+++ b/server/src/utils/logger.ts
@ -0,0 +1,33 @@
+const colors = {
+  reset: '\x1b[0m',
+  red: '\x1b[31m',
+  green: '\x1b[32m',
+  yellow: '\x1b[33m',
+  blue: '\x1b[34m',
+  cyan: '\x1b[36m',
+  gray: '\x1b[90m',
+};
+
+export function log(level: 'info' | 'warn' | 'error' | 'debug', message: string, meta?: unknown): void {
+  const timestamp = new Date().toISOString();
+  const levelColor = {
+    info: colors.green,
+    warn: colors.yellow,
+    error: colors.red,
+    debug: colors.gray,
+  }[level];
+
+  const prefix = `[${timestamp}] ${levelColor}[${level.toUpperCase()}]${colors.reset}`;
+  console.log(prefix, message);
+
+  if (meta) {
+    console.log(meta);
+  }
+}
+
+export const logger = {
+  info: (message: string, meta?: unknown) => log('info', message, meta),
+  warn: (message: string, meta?: unknown) => log('warn', message, meta),
+  error: (message: string, meta?: unknown) => log('error', message, meta),
+  debug: (message: string, meta?: unknown) => log('debug', message, meta),
+};
--- a/server/tsconfig.json
+++ b/server/tsconfig.json
@ -0,0 +1,20 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "commonjs",
+    "lib": ["ES2022"],
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true,
+    "moduleResolution": "node"
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist"]
+}
--- a/shared/types.ts
+++ b/shared/types.ts
@ -0,0 +1,131 @@
+export interface User {
+  id: number;
+  api_key: string;
+  name: string;
+  email?: string;
+  is_active: boolean;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface Backend {
+  id: number;
+  name: string;
+  base_url: string;
+  api_key?: string;
+  is_active: boolean;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface Permission {
+  id: number;
+  user_id: number;
+  backend_id: number;
+  created_at: string;
+}
+
+export interface CreateUserData {
+  name: string;
+  email?: string;
+}
+
+export interface CreateBackendData {
+  name: string;
+  base_url: string;
+  api_key?: string;
+}
+
+export interface CreatePermissionData {
+  user_id: number;
+  backend_id: number;
+}
+
+export interface UpdateUserData {
+  name?: string;
+  email?: string;
+  is_active?: boolean;
+}
+
+export interface UpdateBackendData {
+  name?: string;
+  base_url?: string;
+  api_key?: string;
+  is_active?: boolean;
+}
+
+export interface RequestLog {
+  id: number;
+  user_id: number;
+  backend_id: number;
+  endpoint: string;
+  request_model?: string;
+  response_model?: string;
+  prompt_tokens?: number;
+  completion_tokens?: number;
+  total_tokens?: number;
+  status_code: number;
+  response_time_ms?: number;
+  error_message?: string;
+  created_at: string;
+}
+
+export interface UsageStats {
+  id: number;
+  user_id: number;
+  backend_id: number;
+  date: string;
+  total_requests: number;
+  total_tokens: number;
+}
+
+export interface BackendMetrics {
+  id: number;
+  backend_id: number;
+  date: string;
+  total_requests: number;
+  total_tokens: number;
+  avg_response_time_ms: number;
+  error_count: number;
+  success_rate: number;
+}
+
+export interface OpenAIChatMessage {
+  role: 'system' | 'user' | 'assistant';
+  content: string;
+}
+
+export interface OpenAIChatCompletionRequest {
+  model: string;
+  messages: OpenAIChatMessage[];
+  temperature?: number;
+  max_tokens?: number;
+  top_p?: number;
+  frequency_penalty?: number;
+  presence_penalty?: number;
+  stream?: boolean;
+}
+
+export interface OpenAIChatCompletionResponse {
+  id: string;
+  object: string;
+  created: number;
+  model: string;
+  choices: {
+    index: number;
+    message: OpenAIChatMessage;
+    finish_reason: string;
+  }[];
+  usage: {
+    prompt_tokens: number;
+    completion_tokens: number;
+    total_tokens: number;
+  };
+}
+
+export interface OpenAIModel {
+  id: string;
+  object: string;
+  created: number;
+  owned_by: string;
+}