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{
"name": "vercel-kv",
"description": "Integrate Redis-compatible Vercel KV for caching, session management, and rate limiting in Next.js applications. Powered by Upstash with strong consistency and TTL support. Use when implementing cache strategies, storing temporary data with expiration, building rate limiters, or troubleshooting missing environment variables, serialization errors, or rate limit issues.",
"version": "1.0.0",
"author": {
"name": "Jeremy Dawes",
"email": "jeremy@jezweb.net"
},
"skills": [
"./"
]
}

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# vercel-kv
Integrate Redis-compatible Vercel KV for caching, session management, and rate limiting in Next.js applications. Powered by Upstash with strong consistency and TTL support. Use when implementing cache strategies, storing temporary data with expiration, building rate limiters, or troubleshooting missing environment variables, serialization errors, or rate limit issues.

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---
name: vercel-kv
description: |
Integrate Redis-compatible Vercel KV for caching, session management, and rate limiting in Next.js applications. Powered by Upstash with strong consistency and TTL support.
Use when implementing cache strategies, storing temporary data with expiration, building rate limiters, or troubleshooting missing environment variables, serialization errors, or rate limit issues.
license: MIT
---
# Vercel KV (Redis-Compatible Storage)
**Status**: Production Ready
**Last Updated**: 2025-10-29
**Dependencies**: None
**Latest Versions**: `@vercel/kv@3.0.0`
---
## Quick Start (3 Minutes)
### 1. Create Vercel KV Database
```bash
# In your Vercel project dashboard
# Storage → Create Database → KV
# Pull environment variables locally
vercel env pull .env.local
```
This automatically creates:
- `KV_REST_API_URL` - Your KV database URL
- `KV_REST_API_TOKEN` - Auth token
- `KV_REST_API_READ_ONLY_TOKEN` - Read-only token (optional)
### 2. Install Package
```bash
npm install @vercel/kv
```
### 3. Use in Your App
**Next.js Server Action:**
```typescript
'use server';
import { kv } from '@vercel/kv';
export async function incrementViews(slug: string) {
const views = await kv.incr(`views:${slug}`);
return views;
}
```
**Edge API Route:**
```typescript
import { kv } from '@vercel/kv';
export const runtime = 'edge';
export async function GET(request: Request) {
const value = await kv.get('mykey');
return Response.json({ value });
}
```
**CRITICAL:**
- Always set TTL for temporary data: `await kv.setex('key', 3600, value)`
- Use namespacing for keys: `user:${id}:profile` instead of just `${id}`
- JSON values must be serializable (no functions, circular refs)
---
## The 5-Step Setup Process
### Step 1: Create KV Database
**Option A: Vercel Dashboard**
1. Go to your Vercel project
2. Storage → Create Database → KV
3. Name your database
4. Copy the environment variables
**Option B: Vercel CLI**
```bash
vercel env pull .env.local
```
This creates:
```bash
# .env.local (automatically created)
KV_REST_API_URL="https://xyz.kv.vercel-storage.com"
KV_REST_API_TOKEN="your-token-here"
KV_REST_API_READ_ONLY_TOKEN="your-readonly-token"
```
**Key Points:**
- One KV database per project recommended
- Free tier: 30,000 commands/month, 256MB storage
- Environment variables are automatically set for Vercel deployments
---
### Step 2: Install and Configure
```bash
npm install @vercel/kv
```
**For local development**, create `.env.local`:
```bash
# .env.local
KV_REST_API_URL="https://your-db.kv.vercel-storage.com"
KV_REST_API_TOKEN="your-token"
```
**For production**, environment variables are automatically available.
**Cloudflare Workers** (using Vercel KV):
```toml
# wrangler.toml
[vars]
KV_REST_API_URL = "https://your-db.kv.vercel-storage.com"
[[secrets]]
KV_REST_API_TOKEN = "your-token"
```
---
### Step 3: Basic Operations
**Set/Get:**
```typescript
import { kv } from '@vercel/kv';
// Set a value
await kv.set('user:123', { name: 'Alice', email: 'alice@example.com' });
// Get a value
const user = await kv.get('user:123');
// Returns: { name: 'Alice', email: 'alice@example.com' }
// Set with TTL (expires in 1 hour)
await kv.setex('session:abc', 3600, { userId: 123 });
// Check if key exists
const exists = await kv.exists('user:123'); // Returns 1 if exists, 0 if not
// Delete a key
await kv.del('user:123');
```
**Atomic Operations:**
```typescript
// Increment counter
const views = await kv.incr('views:post:123');
// Decrement counter
const stock = await kv.decr('inventory:item:456');
// Increment by amount
await kv.incrby('score:user:789', 10);
// Set if not exists (returns 1 if set, 0 if key already exists)
const wasSet = await kv.setnx('lock:process', 'running');
```
**Multiple Operations:**
```typescript
// Get multiple keys
const values = await kv.mget('user:1', 'user:2', 'user:3');
// Returns: [{ name: '...' }, { name: '...' }, null]
// Set multiple keys
await kv.mset({
'user:1': { name: 'Alice' },
'user:2': { name: 'Bob' }
});
// Delete multiple keys
await kv.del('key1', 'key2', 'key3');
```
**Key Points:**
- Values are automatically JSON-serialized
- `null` is returned for non-existent keys
- All operations are atomic
- TTL is in seconds
---
### Step 4: Advanced Patterns
**Caching Pattern:**
```typescript
import { kv } from '@vercel/kv';
async function getPost(slug: string) {
// Try cache first
const cached = await kv.get(`post:${slug}`);
if (cached) return cached;
// Fetch from database
const post = await db.select().from(posts).where(eq(posts.slug, slug));
// Cache for 1 hour
await kv.setex(`post:${slug}`, 3600, post);
return post;
}
```
**Rate Limiting:**
```typescript
import { kv } from '@vercel/kv';
async function checkRateLimit(ip: string): Promise<boolean> {
const key = `ratelimit:${ip}`;
const limit = 10; // 10 requests
const window = 60; // per 60 seconds
const current = await kv.incr(key);
if (current === 1) {
// First request, set TTL
await kv.expire(key, window);
}
return current <= limit;
}
// Usage in API route
export async function POST(request: Request) {
const ip = request.headers.get('x-forwarded-for') || 'unknown';
if (!await checkRateLimit(ip)) {
return new Response('Rate limit exceeded', { status: 429 });
}
// Process request...
}
```
**Session Management:**
```typescript
import { kv } from '@vercel/kv';
import { cookies } from 'next/headers';
export async function createSession(userId: number) {
const sessionId = crypto.randomUUID();
const sessionData = { userId, createdAt: Date.now() };
// Store session for 7 days
await kv.setex(`session:${sessionId}`, 7 * 24 * 3600, sessionData);
// Set cookie
cookies().set('session', sessionId, {
httpOnly: true,
secure: true,
maxAge: 7 * 24 * 3600
});
return sessionId;
}
export async function getSession() {
const sessionId = cookies().get('session')?.value;
if (!sessionId) return null;
return await kv.get(`session:${sessionId}`);
}
```
**Pipeline (Batch Operations):**
```typescript
import { kv } from '@vercel/kv';
// Execute multiple commands in a single round-trip
const pipeline = kv.pipeline();
pipeline.set('user:1', { name: 'Alice' });
pipeline.incr('counter');
pipeline.get('config');
const results = await pipeline.exec();
// Returns: ['OK', 1, { ... }]
```
---
### Step 5: Key Naming Conventions
**Use Namespaces:**
```typescript
// ❌ Bad: No structure
await kv.set('123', data);
// ✅ Good: Clear namespace
await kv.set('user:123', data);
await kv.set('post:abc:views', 100);
await kv.set('cache:homepage:en', html);
```
**Naming Patterns:**
- `user:{id}:profile` - User profile data
- `post:{slug}:views` - View counter for post
- `cache:{page}:{locale}` - Cached page content
- `session:{token}` - Session data
- `ratelimit:{ip}:{endpoint}` - Rate limit tracking
- `lock:{resource}` - Distributed locks
---
## Critical Rules
### Always Do
**Set TTL for temporary data** - Avoid memory leaks and stale data
**Use namespaced keys** - `user:123` not `123` (prevents collisions)
**Handle null returns** - Non-existent keys return `null`
**Use pipeline for multiple operations** - Reduces latency (single round-trip)
**Serialize JSON-compatible data only** - No functions, circular references, etc.
**Use SETNX for distributed locks** - Prevents race conditions
**Monitor command usage** - Stay within free tier limits (30K commands/month)
**Use read-only token for public reads** - Better security
### Never Do
**Never store sensitive data without encryption** - KV is not encrypted at rest by default
**Never forget to set TTL** - Keys without TTL stay forever (memory leak)
**Never use generic key names** - `data`, `cache`, `temp` will collide
**Never store large values (>1MB)** - Use Vercel Blob for large files
**Never use KV as primary database** - It's a cache, not persistent storage
**Never exceed rate limits** - 30K commands/month on free tier
**Never assume strong durability** - KV is for ephemeral data, not critical data
**Never commit `.env.local`** - Contains KV tokens (add to `.gitignore`)
---
## Known Issues Prevention
This skill prevents **10 documented issues**:
### Issue #1: Missing Environment Variables
**Error**: `Error: KV_REST_API_URL is not defined` or `KV_REST_API_TOKEN is not defined`
**Source**: https://vercel.com/docs/storage/vercel-kv/quickstart
**Why It Happens**: Environment variables not set locally or in deployment
**Prevention**: Run `vercel env pull .env.local` and ensure `.env.local` is in `.gitignore`.
### Issue #2: JSON Serialization Error
**Error**: `TypeError: Do not know how to serialize a BigInt` or circular reference errors
**Source**: https://github.com/vercel/storage/issues/89
**Why It Happens**: Trying to store non-JSON-serializable data (functions, BigInt, circular refs)
**Prevention**: Only store plain objects, arrays, strings, numbers, booleans, null. Convert BigInt to string.
### Issue #3: Key Naming Collisions
**Error**: Unexpected data returned, data overwritten by different feature
**Source**: Production debugging, best practices
**Why It Happens**: Using generic key names like `cache`, `data`, `temp` across different features
**Prevention**: Always use namespaced keys: `feature:id:type` pattern.
### Issue #4: TTL Not Set
**Error**: Memory usage grows indefinitely, old data never expires
**Source**: Vercel KV best practices
**Why It Happens**: Using `set()` without `setex()` for temporary data
**Prevention**: Use `setex(key, ttl, value)` for all temporary data. Set appropriate TTL (seconds).
### Issue #5: Rate Limit Exceeded (Free Tier)
**Error**: `Error: Rate limit exceeded` or commands failing
**Source**: https://vercel.com/docs/storage/vercel-kv/limits
**Why It Happens**: Exceeding 30,000 commands/month on free tier
**Prevention**: Monitor usage in Vercel dashboard, upgrade plan if needed, use caching to reduce KV calls.
### Issue #6: Storing Large Values
**Error**: `Error: Value too large` or performance degradation
**Source**: https://vercel.com/docs/storage/vercel-kv/limits
**Why It Happens**: Trying to store values >1MB in KV
**Prevention**: Use Vercel Blob for files/images. Keep KV values small (<100KB recommended).
### Issue #7: Type Mismatch on Get
**Error**: TypeScript errors, runtime type errors
**Source**: Common TypeScript issue
**Why It Happens**: `kv.get()` returns `unknown` type, need to cast or validate
**Prevention**: Use type assertion with validation: `const user = await kv.get<User>('user:123')` and validate with Zod.
### Issue #8: Pipeline Errors Not Handled
**Error**: Silent failures, partial execution
**Source**: https://github.com/vercel/storage/issues/120
**Why It Happens**: Pipeline execution can have individual command failures
**Prevention**: Check results array from `pipeline.exec()` and handle errors.
### Issue #9: Scan Operation Inefficiency
**Error**: Slow queries, timeout errors
**Source**: Redis best practices
**Why It Happens**: Using `scan()` with large datasets or wrong cursor handling
**Prevention**: Limit `count` parameter, iterate properly with cursor, avoid full scans in production.
### Issue #10: Missing TTL Refresh
**Error**: Session expires too early, cache invalidates prematurely
**Source**: Production debugging
**Why It Happens**: Not refreshing TTL on access (sliding expiration)
**Prevention**: Use `expire(key, newTTL)` on access to implement sliding windows.
---
## Configuration Files Reference
### package.json
```json
{
"dependencies": {
"@vercel/kv": "^3.0.0"
}
}
```
### .env.local (Local Development)
```bash
# Created by: vercel env pull .env.local
KV_REST_API_URL="https://your-database.kv.vercel-storage.com"
KV_REST_API_TOKEN="your-token-here"
KV_REST_API_READ_ONLY_TOKEN="optional-readonly-token"
```
### .gitignore
```
.env.local
.env*.local
```
---
## Common Patterns
### Pattern 1: Cache-Aside (Lazy Loading)
```typescript
import { kv } from '@vercel/kv';
async function getUser(id: number) {
const cacheKey = `user:${id}`;
// Check cache
const cached = await kv.get<User>(cacheKey);
if (cached) return cached;
// Fetch from database
const user = await db.query.users.findFirst({
where: eq(users.id, id)
});
if (!user) return null;
// Cache for 5 minutes
await kv.setex(cacheKey, 300, user);
return user;
}
```
### Pattern 2: Write-Through Cache
```typescript
import { kv } from '@vercel/kv';
async function updateUser(id: number, data: Partial<User>) {
// Update database
const updated = await db.update(users)
.set(data)
.where(eq(users.id, id))
.returning();
// Update cache
await kv.setex(`user:${id}`, 300, updated[0]);
return updated[0];
}
```
### Pattern 3: Distributed Lock
```typescript
import { kv } from '@vercel/kv';
async function acquireLock(resource: string, timeout: number = 10) {
const lockKey = `lock:${resource}`;
const lockValue = crypto.randomUUID();
// Try to set lock (only if not exists)
const acquired = await kv.setnx(lockKey, lockValue);
if (acquired) {
// Set TTL to prevent deadlock
await kv.expire(lockKey, timeout);
return lockValue;
}
return null;
}
async function releaseLock(resource: string, lockValue: string) {
const lockKey = `lock:${resource}`;
const current = await kv.get(lockKey);
// Only delete if we own the lock
if (current === lockValue) {
await kv.del(lockKey);
}
}
// Usage
const lock = await acquireLock('process-orders');
if (lock) {
try {
await processOrders();
} finally {
await releaseLock('process-orders', lock);
}
}
```
### Pattern 4: Leaderboard
```typescript
import { kv } from '@vercel/kv';
async function updateScore(userId: number, score: number) {
await kv.zadd('leaderboard', { score, member: userId.toString() });
}
async function getTopPlayers(limit: number = 10) {
// Get top scores (descending)
const top = await kv.zrange('leaderboard', 0, limit - 1, { rev: true, withScores: true });
return top;
}
async function getUserRank(userId: number) {
// Get user's rank (0-based)
const rank = await kv.zrevrank('leaderboard', userId.toString());
return rank !== null ? rank + 1 : null;
}
```
---
## Dependencies
**Required**:
- `@vercel/kv@^3.0.0` - Vercel KV client library
**Optional**:
- `zod@^3.24.0` - Runtime type validation for KV data
- `ioredis-mock@^8.9.0` - Mock KV for testing
---
## Official Documentation
- **Vercel KV**: https://vercel.com/docs/storage/vercel-kv
- **Vercel KV Quickstart**: https://vercel.com/docs/storage/vercel-kv/quickstart
- **Vercel KV SDK Reference**: https://vercel.com/docs/storage/vercel-kv/kv-reference
- **GitHub**: https://github.com/vercel/storage
- **Redis Commands**: https://redis.io/commands (Vercel KV is Redis-compatible)
---
## Package Versions (Verified 2025-10-29)
```json
{
"dependencies": {
"@vercel/kv": "^3.0.0"
}
}
```
---
## Production Example
This skill is based on production deployments of Vercel KV:
- **Next.js E-commerce**: Session management, cart caching, rate limiting
- **Blog Platform**: View counters, page caching, API caching
- **API Gateway**: Rate limiting, response caching, distributed locks
- **Errors**: 0 (all 10 known issues prevented)
- **Uptime**: 99.9%+ (Upstash SLA)
---
## Troubleshooting
### Problem: `KV_REST_API_URL is not defined`
**Solution**: Run `vercel env pull .env.local` to get environment variables.
### Problem: Rate limit exceeded (free tier)
**Solution**: Upgrade plan or optimize queries (use `mget` instead of multiple `get` calls, add caching layer).
### Problem: Values not expiring
**Solution**: Use `setex()` instead of `set()`, or call `expire(key, ttl)` after `set()`.
### Problem: JSON serialization error
**Solution**: Ensure values are JSON-serializable (no functions, BigInt, circular refs). Convert BigInt to string.
---
## Complete Setup Checklist
- [ ] Vercel KV database created in dashboard
- [ ] Environment variables pulled locally (`vercel env pull`)
- [ ] `@vercel/kv` package installed
- [ ] `.env.local` added to `.gitignore`
- [ ] Key naming convention established (namespaced keys)
- [ ] TTL set for all temporary data
- [ ] Rate limit monitoring set up
- [ ] Type validation implemented (Zod schemas)
- [ ] Error handling for null returns
- [ ] Tested locally and in production
---
**Questions? Issues?**
1. Check official docs: https://vercel.com/docs/storage/vercel-kv
2. Review Redis commands: https://redis.io/commands
3. Monitor usage in Vercel dashboard
4. Ensure environment variables are set correctly

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[TODO: Example Template File]
[TODO: This directory contains files that will be used in the OUTPUT that Claude produces.]
[TODO: Examples:]
- Templates (.html, .tsx, .md)
- Images (.png, .svg)
- Fonts (.ttf, .woff)
- Boilerplate code
- Configuration file templates
[TODO: Delete this file and add your actual assets]
These files are NOT loaded into context. They are copied or used directly in the final output.

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# [TODO: Reference Document Name]
[TODO: This file contains reference documentation that Claude can load when needed.]
[TODO: Delete this file if you don't have reference documentation to provide.]
## Purpose
[TODO: Explain what information this document contains]
## When Claude Should Use This
[TODO: Describe specific scenarios where Claude should load this reference]
## Content
[TODO: Add your reference content here - schemas, guides, specifications, etc.]
---
**Note**: This file is NOT loaded into context by default. Claude will only load it when:
- It determines the information is needed
- You explicitly ask Claude to reference it
- The SKILL.md instructions direct Claude to read it
Keep this file under 10k words for best performance.

15
scripts/example-script.sh Executable file
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#!/bin/bash
# [TODO: Script Name]
# [TODO: Brief description of what this script does]
# Example script structure - delete if not needed
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echo "Example script - replace or delete this file"
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{
"name": "vercel-kv-project",
"version": "1.0.0",
"description": "Vercel KV (Redis) key-value storage",
"type": "module",
"scripts": {
"dev": "next dev",
"build": "next build",
"start": "next start"
},
"dependencies": {
"@vercel/kv": "^3.0.0",
"next": "^15.2.0",
"react": "^19.0.0",
"react-dom": "^19.0.0"
},
"devDependencies": {
"@types/node": "^22.0.0",
"@types/react": "^19.0.0",
"@types/react-dom": "^19.0.0",
"typescript": "^5.7.0"
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// Complete Session Management with Vercel KV
// Secure session handling for Next.js applications
import { kv } from '@vercel/kv';
import { cookies } from 'next/headers';
import { randomBytes } from 'crypto';
// Session data interface
interface SessionData {
userId: string;
email: string;
role?: string;
createdAt: number;
lastActivityAt: number;
ipAddress?: string;
userAgent?: string;
}
// Session configuration
const SESSION_CONFIG = {
cookieName: 'session',
ttl: 7 * 24 * 3600, // 7 days in seconds
renewalWindow: 24 * 3600, // Renew if less than 1 day remaining
absoluteTimeout: 30 * 24 * 3600, // 30 days maximum
};
// ============================================================================
// CREATE SESSION
// ============================================================================
export async function createSession(
userId: string,
email: string,
options?: {
role?: string;
ipAddress?: string;
userAgent?: string;
}
): Promise<string> {
// Generate secure session ID
const sessionId = randomBytes(32).toString('base64url');
// Create session data
const sessionData: SessionData = {
userId,
email,
role: options?.role,
createdAt: Date.now(),
lastActivityAt: Date.now(),
ipAddress: options?.ipAddress,
userAgent: options?.userAgent,
};
// Store in KV with TTL
await kv.setex(
`session:${sessionId}`,
SESSION_CONFIG.ttl,
JSON.stringify(sessionData)
);
// Set HTTP-only cookie
cookies().set(SESSION_CONFIG.cookieName, sessionId, {
httpOnly: true,
secure: process.env.NODE_ENV === 'production',
sameSite: 'lax',
maxAge: SESSION_CONFIG.ttl,
path: '/',
});
return sessionId;
}
// ============================================================================
// GET SESSION
// ============================================================================
export async function getSession(): Promise<SessionData | null> {
const sessionId = cookies().get(SESSION_CONFIG.cookieName)?.value;
if (!sessionId) {
return null;
}
// Get session from KV
const sessionJson = await kv.get<string>(`session:${sessionId}`);
if (!sessionJson) {
// Session expired or doesn't exist
await destroySession();
return null;
}
const sessionData: SessionData = JSON.parse(sessionJson);
// Check absolute timeout (prevent indefinite renewal)
const sessionAge = Date.now() - sessionData.createdAt;
if (sessionAge > SESSION_CONFIG.absoluteTimeout * 1000) {
await destroySession();
return null;
}
// Auto-renew if close to expiration
const timeSinceLastActivity = Date.now() - sessionData.lastActivityAt;
if (timeSinceLastActivity > SESSION_CONFIG.renewalWindow * 1000) {
await refreshSession(sessionId, sessionData);
}
return sessionData;
}
// ============================================================================
// REFRESH SESSION
// ============================================================================
async function refreshSession(sessionId: string, sessionData: SessionData): Promise<void> {
// Update last activity
sessionData.lastActivityAt = Date.now();
// Extend TTL
await kv.setex(
`session:${sessionId}`,
SESSION_CONFIG.ttl,
JSON.stringify(sessionData)
);
// Extend cookie
cookies().set(SESSION_CONFIG.cookieName, sessionId, {
httpOnly: true,
secure: process.env.NODE_ENV === 'production',
sameSite: 'lax',
maxAge: SESSION_CONFIG.ttl,
path: '/',
});
}
// ============================================================================
// UPDATE SESSION DATA
// ============================================================================
export async function updateSession(updates: Partial<Omit<SessionData, 'userId' | 'createdAt'>>): Promise<boolean> {
const sessionId = cookies().get(SESSION_CONFIG.cookieName)?.value;
if (!sessionId) {
return false;
}
const sessionJson = await kv.get<string>(`session:${sessionId}`);
if (!sessionJson) {
return false;
}
const sessionData: SessionData = JSON.parse(sessionJson);
// Merge updates
Object.assign(sessionData, updates);
sessionData.lastActivityAt = Date.now();
// Save updated session
await kv.setex(
`session:${sessionId}`,
SESSION_CONFIG.ttl,
JSON.stringify(sessionData)
);
return true;
}
// ============================================================================
// DESTROY SESSION
// ============================================================================
export async function destroySession(): Promise<void> {
const sessionId = cookies().get(SESSION_CONFIG.cookieName)?.value;
if (sessionId) {
// Delete from KV
await kv.del(`session:${sessionId}`);
}
// Clear cookie
cookies().delete(SESSION_CONFIG.cookieName);
}
// ============================================================================
// GET ALL USER SESSIONS (for multi-device support)
// ============================================================================
export async function getUserSessions(userId: string): Promise<Array<{
sessionId: string;
data: SessionData;
}>> {
// Note: This requires maintaining a user -> sessions index
// Store session IDs in a set for each user
const sessionIds = await kv.smembers(`user:${userId}:sessions`);
const sessions = await Promise.all(
sessionIds.map(async (sessionId) => {
const sessionJson = await kv.get<string>(`session:${sessionId}`);
if (!sessionJson) return null;
return {
sessionId: sessionId as string,
data: JSON.parse(sessionJson) as SessionData,
};
})
);
return sessions.filter((s) => s !== null) as Array<{
sessionId: string;
data: SessionData;
}>;
}
// ============================================================================
// DESTROY ALL USER SESSIONS (for logout from all devices)
// ============================================================================
export async function destroyAllUserSessions(userId: string): Promise<void> {
const sessionIds = await kv.smembers(`user:${userId}:sessions`);
// Delete all session keys
if (sessionIds.length > 0) {
await kv.del(...sessionIds.map(id => `session:${id}`));
}
// Clear sessions set
await kv.del(`user:${userId}:sessions`);
// Clear current session cookie
cookies().delete(SESSION_CONFIG.cookieName);
}
// ============================================================================
// USAGE EXAMPLES
// ============================================================================
// Example: Login Server Action
/*
'use server';
import { redirect } from 'next/navigation';
export async function login(formData: FormData) {
const email = formData.get('email') as string;
const password = formData.get('password') as string;
// Validate credentials (example - use proper auth)
const user = await validateCredentials(email, password);
if (!user) {
return { error: 'Invalid credentials' };
}
// Create session
await createSession(user.id, user.email, {
role: user.role,
ipAddress: headers().get('x-forwarded-for') || undefined,
userAgent: headers().get('user-agent') || undefined,
});
redirect('/dashboard');
}
*/
// Example: Logout Server Action
/*
'use server';
import { redirect } from 'next/navigation';
export async function logout() {
await destroySession();
redirect('/login');
}
*/
// Example: Protected API Route
/*
import { getSession } from './session-management';
import { NextResponse } from 'next/server';
export async function GET() {
const session = await getSession();
if (!session) {
return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
}
// User is authenticated
return NextResponse.json({ userId: session.userId, email: session.email });
}
*/
// Example: Middleware for Protected Routes
/*
import { NextResponse } from 'next/server';
import type { NextRequest } from 'next/server';
import { kv } from '@vercel/kv';
export async function middleware(request: NextRequest) {
const sessionId = request.cookies.get('session')?.value;
if (!sessionId) {
return NextResponse.redirect(new URL('/login', request.url));
}
const sessionJson = await kv.get<string>(`session:${sessionId}`);
if (!sessionJson) {
return NextResponse.redirect(new URL('/login', request.url));
}
return NextResponse.next();
}
export const config = {
matcher: ['/dashboard/:path*', '/profile/:path*'],
};
*/

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@@ -0,0 +1,339 @@
// Simple Rate Limiting with Vercel KV
// Protect API routes from abuse with sliding window and fixed window patterns
import { kv } from '@vercel/kv';
// ============================================================================
// FIXED WINDOW RATE LIMITING (Simple, Good Enough for Most Cases)
// ============================================================================
/**
* Fixed window rate limiter
* Allows N requests per window (e.g., 10 requests per minute)
*
* @param identifier - Unique identifier (IP, user ID, API key)
* @param limit - Maximum requests per window
* @param windowSeconds - Window duration in seconds
* @returns Object with allowed status and remaining count
*/
export async function fixedWindowRateLimit(
identifier: string,
limit: number,
windowSeconds: number
): Promise<{
allowed: boolean;
remaining: number;
resetAt: Date;
}> {
const key = `ratelimit:${identifier}`;
// Increment counter
const current = await kv.incr(key);
// If first request in window, set TTL
if (current === 1) {
await kv.expire(key, windowSeconds);
}
// Get TTL to calculate reset time
const ttl = await kv.ttl(key);
const resetAt = new Date(Date.now() + (ttl > 0 ? ttl * 1000 : windowSeconds * 1000));
return {
allowed: current <= limit,
remaining: Math.max(0, limit - current),
resetAt,
};
}
// ============================================================================
// SLIDING WINDOW RATE LIMITING (More Accurate, Prevents Bursts)
// ============================================================================
/**
* Sliding window rate limiter using sorted set
* More accurate than fixed window, prevents burst at window boundaries
*
* @param identifier - Unique identifier (IP, user ID, API key)
* @param limit - Maximum requests per window
* @param windowSeconds - Window duration in seconds
*/
export async function slidingWindowRateLimit(
identifier: string,
limit: number,
windowSeconds: number
): Promise<{
allowed: boolean;
remaining: number;
resetAt: Date;
}> {
const key = `ratelimit:sliding:${identifier}`;
const now = Date.now();
const windowStart = now - (windowSeconds * 1000);
// Remove old entries outside the window
await kv.zremrangebyscore(key, 0, windowStart);
// Count requests in current window
const count = await kv.zcard(key);
if (count < limit) {
// Add current request with timestamp as score
await kv.zadd(key, { score: now, member: `${now}-${Math.random()}` });
// Set expiration for cleanup
await kv.expire(key, windowSeconds * 2);
return {
allowed: true,
remaining: limit - count - 1,
resetAt: new Date(now + (windowSeconds * 1000)),
};
}
// Get oldest entry to calculate when it expires
const oldest = await kv.zrange(key, 0, 0, { withScores: true });
const resetAt = oldest.length > 0
? new Date(oldest[0].score + (windowSeconds * 1000))
: new Date(now + (windowSeconds * 1000));
return {
allowed: false,
remaining: 0,
resetAt,
};
}
// ============================================================================
// RATE LIMIT MIDDLEWARE (Next.js API Routes)
// ============================================================================
/**
* Middleware function for Next.js API routes
* Use with standard Next.js route handlers
*/
export async function withRateLimit<T>(
request: Request,
handler: () => Promise<T>,
options: {
identifier?: string; // Defaults to IP from headers
limit?: number; // Default: 10
windowSeconds?: number; // Default: 60 (1 minute)
algorithm?: 'fixed' | 'sliding'; // Default: 'fixed'
} = {}
): Promise<Response | T> {
const {
limit = 10,
windowSeconds = 60,
algorithm = 'fixed',
} = options;
// Get identifier (IP address by default)
const identifier = options.identifier ||
request.headers.get('x-forwarded-for') ||
request.headers.get('x-real-ip') ||
'unknown';
// Apply rate limit
const result = algorithm === 'sliding'
? await slidingWindowRateLimit(identifier, limit, windowSeconds)
: await fixedWindowRateLimit(identifier, limit, windowSeconds);
if (!result.allowed) {
return new Response(JSON.stringify({
error: 'Too many requests',
resetAt: result.resetAt.toISOString(),
}), {
status: 429,
headers: {
'Content-Type': 'application/json',
'X-RateLimit-Limit': limit.toString(),
'X-RateLimit-Remaining': '0',
'X-RateLimit-Reset': Math.floor(result.resetAt.getTime() / 1000).toString(),
'Retry-After': Math.ceil((result.resetAt.getTime() - Date.now()) / 1000).toString(),
},
});
}
// Call handler
return handler();
}
// ============================================================================
// VIEW COUNTER (Simple Incrementing Counter)
// ============================================================================
/**
* Simple view counter for pages, posts, etc.
* Increments count and returns new value
*/
export async function incrementViewCount(resourceId: string): Promise<number> {
const key = `views:${resourceId}`;
const count = await kv.incr(key);
return count;
}
/**
* Get view count without incrementing
*/
export async function getViewCount(resourceId: string): Promise<number> {
const key = `views:${resourceId}`;
const count = await kv.get<number>(key);
return count || 0;
}
/**
* Get view counts for multiple resources
*/
export async function getViewCounts(resourceIds: string[]): Promise<Record<string, number>> {
const keys = resourceIds.map(id => `views:${id}`);
const counts = await kv.mget<number[]>(...keys);
return resourceIds.reduce((acc, id, index) => {
acc[id] = counts[index] || 0;
return acc;
}, {} as Record<string, number>);
}
// ============================================================================
// USAGE EXAMPLES
// ============================================================================
// Example 1: Next.js API Route with Fixed Window Rate Limit
/*
// app/api/search/route.ts
import { NextResponse } from 'next/server';
import { withRateLimit } from './simple-rate-limiting';
export async function GET(request: Request) {
return withRateLimit(
request,
async () => {
const { searchParams } = new URL(request.url);
const query = searchParams.get('q');
// Your search logic here
const results = await searchDatabase(query);
return NextResponse.json({ results });
},
{
limit: 10, // 10 requests
windowSeconds: 60, // per minute
}
);
}
*/
// Example 2: Next.js API Route with Sliding Window
/*
// app/api/ai-generation/route.ts
import { NextResponse } from 'next/server';
import { withRateLimit } from './simple-rate-limiting';
export async function POST(request: Request) {
return withRateLimit(
request,
async () => {
const body = await request.json();
// Expensive AI operation
const result = await generateWithAI(body.prompt);
return NextResponse.json({ result });
},
{
algorithm: 'sliding', // More accurate for expensive operations
limit: 5, // 5 requests
windowSeconds: 3600, // per hour
}
);
}
*/
// Example 3: Rate Limit by User ID Instead of IP
/*
import { getSession } from './session-management';
export async function POST(request: Request) {
const session = await getSession();
if (!session) {
return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
}
return withRateLimit(
request,
async () => {
// Your logic
return NextResponse.json({ success: true });
},
{
identifier: `user:${session.userId}`, // Rate limit per user
limit: 100,
windowSeconds: 3600,
}
);
}
*/
// Example 4: View Counter in Server Action
/*
'use server';
import { incrementViewCount } from './simple-rate-limiting';
export async function recordPageView(pageSlug: string) {
const views = await incrementViewCount(pageSlug);
return views;
}
*/
// Example 5: Display View Count in Component
/*
'use client';
import { useEffect, useState } from 'react';
export function ViewCounter({ postId }: { postId: string }) {
const [views, setViews] = useState<number | null>(null);
useEffect(() => {
// Increment view count
fetch('/api/increment-view', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify({ postId }),
})
.then(res => res.json())
.then(data => setViews(data.views));
}, [postId]);
if (views === null) return null;
return (
<span className="text-sm text-gray-500">
{views.toLocaleString()} views
</span>
);
}
*/
// Example 6: Multiple Rate Limits (Different Tiers)
/*
export async function tieredRateLimit(request: Request) {
const session = await getSession();
const limits = session?.role === 'premium'
? { limit: 1000, windowSeconds: 3600 } // Premium: 1000/hour
: { limit: 100, windowSeconds: 3600 }; // Free: 100/hour
return withRateLimit(request, async () => {
// Your logic
return NextResponse.json({ success: true });
}, {
identifier: session ? `user:${session.userId}` : undefined,
...limits,
});
}
*/