What class of response is HTTP 429?

HTTP 429 is a 4xx Client Error response. These indicate a client-side error.

How do I fix HTTP 429 Too Many Requests?

HTTP 429 is a client error. Verify the request URL, method, headers, and body are correct. Consult the API documentation for the endpoint.

Is HTTP 429 an error?

Yes, HTTP 429 is an error — specifically a 4xx Client Error code.

HTTP 429 Too Many Requests: What It Means and When You See It

Quick Answer

HTTP 429 Too Many Requests means the user has sent too many requests in a given time period (rate limiting). The Retry-After header may indicate when to retry.

Why HTTP 429 Occurs

HTTP 429 Too Many Requests means the client has exceeded the API's rate limit. Rate limits prevent abuse, protect servers from overload, and enforce fair usage. The response should include Retry-After (seconds to wait) and optionally X-RateLimit-Limit, X-RateLimit-Remaining, and X-RateLimit-Reset headers. Limits may apply per IP, per API key, per user, or per endpoint.

Handling 429 in Code

Implement exponential backoff: wait 1s, 2s, 4s, 8s between retries. Read the Retry-After header: const retryAfter = parseInt(res.headers["retry-after"] || "1"); await sleep(retryAfter * 1000). For server-side rate limiting (Express): use express-rate-limit. const limiter = rateLimit({ windowMs: 60000, max: 100 }); app.use("/api/", limiter). Returning 429 with a Retry-After header is required by RFC 6585.

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Frequently Asked Questions

Related Values

100

HTTP 100 Continue means the server has received the request headers and the client should proceed to send the request body. It is an interim response used to inform the client to continue.

101

HTTP 101 Switching Protocols indicates the server is switching to the protocol specified in the Upgrade header field. Commonly used when upgrading to WebSocket connections.

200

HTTP 200 OK is the standard success response. The request has succeeded and the server has returned the requested resource in the response body.

201

HTTP 201 Created means the request succeeded and a new resource was created as a result. The Location header typically points to the new resource URL.