In some cases, when your server detects that a user agent is trying to access a specific page too often in a short period of time, it triggers a rate-limiting feature. Check Out Our Video Guide to the 429 Too Many Requests Error What Causes the HTTP 429 Too Many Requests Error The 429 status code is intended for use with rate-limiting schemes. The HTTP 429 error is returned when a user has sent too many requests within a short period of time.