HTTP 429 Too Many Requests
Plain-English meaning
The client sent requests faster than allowed by a rate limit.
Why it happens
Gateway or app applies per-IP, per-user, or global quotas.
Common causes
- Retry storms after transient failures
- Client missing exponential backoff
- Bot/scraper traffic spikes
- Rate thresholds configured too low
What to check first
Read Retry-After, inspect limiter counters, and identify top offending keys/IPs in logs.
How to fix it
Add backoff with jitter, raise limits for trusted callers, and cache expensive endpoints to reduce request pressure.
Example signal
HTTP/1.1 429 Too Many Requests Retry-After: 60
Related links
404 · 429 · 500 · 502 · 503 · 504 · Cloudflare 522 · Nginx 499 · ERR_CONNECTION_REFUSED
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