Cloudflare Rate Limiting for APIs

What this problem means

Your API needs rate limiting to prevent abuse. Cloudflare can enforce limits at the edge—before requests reach your origin. No code changes. Configure rules in the dashboard.

Why this matters

- Abuse prevention: Rate limiting slows down scrapers and attackers.

- Cost control: Fewer abusive requests = lower bills.

- No code changes: Cloudflare handles it at the edge.

Real-world example

A startup had a public API with no rate limits. A script was written to automate millions of requests. They added Cloudflare rate limiting—100 requests per minute per IP—in 15 minutes. Abuse dropped by 95%. No code deployment required.

How to fix it

1. Create a rate limiting rule: In Cloudflare, go to Security > WAF > Rate limiting rules.

2. Define the match: Match by URI path (e.g., /api/*) or hostname.

3. Set threshold: e.g., 100 requests per minute per IP.

4. Choose action: Block, challenge, or log. Block is most effective.

5. Test: Verify legitimate traffic still works.

Tools and configurations

- Cloudflare WAF: Rate limiting rules.

- Match conditions: URI path, hostname, country, etc.

- Actions: Block, challenge (CAPTCHA), or log.

- Bypass: Add exceptions for known good IPs (e.g., your office).

Common mistakes

- Setting limits too low (blocks legitimate users).

- Only limiting by IP (proxies bypass—but still helps).

- No monitoring—verify the rule is working.

Quick checklist

- [ ] Create rate limiting rule for /api/* or your API path

- [ ] Set threshold (e.g., 100 req/min per IP)

- [ ] Choose block action

- [ ] Add bypass for known good IPs if needed

- [ ] Test with legitimate traffic