How do I fix an HTTP 429 error?

Honor Retry-After exactly; absent it, use exponential backoff with jitter — never immediate retries. Batch and cache client-side: the cheapest request is the one not sent. If limits are per-key, split keys per service; if per-IP behind NAT, talk to the provider about higher tiers. Server-side: always send Retry-After — clients without it guess, and they guess aggressively.

429 Too Many Requests

The rate limiter speaking: this client has sent more requests than allowed in the current window. Well-behaved servers include Retry-After (seconds or a date) and often X-RateLimit-* headers describing the quota.

What usually causes it

Genuine traffic bursts (loops without delays, parallel batch jobs)
Shared rate-limit keys (whole office behind one IP; one API key across services)
Retry storms: naive retry-on-429 amplifying the overload

How to debug and fix it

Honor Retry-After exactly; absent it, use exponential backoff with jitter — never immediate retries.
Batch and cache client-side: the cheapest request is the one not sent.
If limits are per-key, split keys per service; if per-IP behind NAT, talk to the provider about higher tiers.
Server-side: always send Retry-After — clients without it guess, and they guess aggressively.

Easily confused with

503Service Unavailable
403Forbidden
408Request Timeout

Debugging an API? Build and inspect requests, check response headers, or read the full status-code debugging guide.