What is Rate Limiting?

Rate limiting is a technique to control the rate of requests sent to an API, protecting your application from abuse, DoS attacks, and excessive resource consumption. Frontend Accelerator includes built-in rate limiting for API routes using middleware.

Rate limiting:

// middleware.ts with rate limiting
import { Ratelimit } from '@upstash/ratelimit';
import { Redis } from '@upstash/redis';

const ratelimit = new Ratelimit({
  redis: Redis.fromEnv(),
  limiter: Ratelimit.slidingWindow(10, '10 s'),
});

export async function middleware(request: NextRequest) {
  const ip = request.ip ?? '127.0.0.1';
  const { success } = await ratelimit.limit(ip);
  
  if (!success) {
    return new Response('Too Many Requests', { status: 429 });
  }
  
  return NextResponse.next();
}

Rate limiting strategies:

• Fixed window: Count requests in fixed time periods
• Sliding window: Smooth rate limits across rolling time windows
• Token bucket: Allow bursts while maintaining average rate
• Per-user limits: Different limits for authenticated vs anonymous users

Key benefits:

• Prevent abuse: Block malicious users from overwhelming your API
• Cost control: Limit resource usage and prevent unexpected bills
• Fair usage: Ensure all users get reasonable access to resources
• DDoS protection: First line of defense against denial-of-service attacks

AI-Friendly: Rate limiting follows clear algorithmic patterns that AI can implement and optimize. AI can suggest appropriate rate limits based on endpoint sensitivity, generate rate limiting middleware, implement tiered limits for different user types, and create informative error responses.