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What do HTTP status codes mean?

Browse the complete reference of 63 HTTP status codes organized by category — 1xx informational, 2xx success, 3xx redirection, 4xx client error, 5xx server error. Each code includes a description, common causes, and how to handle it. Search or filter to find any code quickly.

Look up status code

Input

Code: 429

Output

429 Too Many Requests

Category: Client Error (4xx)
Meaning: Rate limit exceeded

Common headers:
  Retry-After: 60
  X-RateLimit-Remaining: 0

Use when: API rate limiting,
  throttling user requests

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HTTP Status Code Reference

Complete reference for all HTTP response status codes. Search by code or name, filter by category, and click any code for detailed explanations.

61 status codes

1xxInformational

2xxSuccess

3xxRedirection

4xxClient Error

5xxServer Error

Quick reference — most common status codes

Code	Meaning	Common Use
200	OK	Successful request
201	Created	Resource created (POST)
204	No Content	Successful delete or update
301	Moved Permanently	URL/domain migration
302	Found	Temporary redirect
304	Not Modified	Cache hit — use local copy
400	Bad Request	Invalid request body/params
401	Unauthorized	Missing/invalid auth
403	Forbidden	Insufficient permissions
404	Not Found	Resource doesn't exist
409	Conflict	Version/state conflict
422	Unprocessable	Validation error
429	Too Many Requests	Rate limited
500	Internal Server Error	Unhandled server bug
502	Bad Gateway	Upstream server down
503	Service Unavailable	Maintenance/overload

REST API cheat sheet — which codes to return

GET /resources

200 with the list. 304 if cached.

GET /resources/:id

200 with the resource. 404 if not found.

POST /resources

201 + Location header. 400/422 for validation. 409 for duplicates.

PUT/PATCH /resources/:id

200 with updated resource, or 204 if no body. 404 if not found.

DELETE /resources/:id

204 on success. 404 if not found (or 204 idempotently).

Any endpoint

401 if not authenticated. 403 if not authorized. 429 if rate limited. 500 for unexpected errors.

Tips & Best Practices

Pro Tip

Use 201 Created for POST success, not 200 OK

200 OK means 'request succeeded.' 201 Created means 'request succeeded AND a new resource was created.' Using the right status code helps API consumers handle responses correctly and makes your API self-documenting.

Common Pitfall

Don't return 200 with an error message in the body

APIs that return `{ status: 200, error: 'Not found' }` break HTTP semantics and make error handling unreliable. HTTP clients, proxies, and monitoring tools rely on status codes. Return 404 for not found, 400 for bad input, 500 for server errors.

Real-World Example

429 Too Many Requests should include Retry-After header

When rate limiting, always include a Retry-After header with the number of seconds until the client can retry. This lets well-behaved clients implement exponential backoff correctly instead of hammering your API in a tight loop.

Security Note

Don't leak implementation details in error responses

A 500 error that returns a stack trace, database connection string, or internal path gives attackers a roadmap. In production, return generic error messages with status codes. Log detailed errors server-side where only your team can see them.

Frequently Asked Questions

What is the difference between 301 and 302 HTTP redirects?

HTTP 301 Moved Permanently indicates the resource has been permanently relocated. Search engines transfer link equity to the new URL and update their index. Browsers cache 301 redirects aggressively. HTTP 302 Found indicates a temporary redirect. Search engines keep the original URL indexed. Use 301 for domain migrations and permanently moved pages. Use 302 for maintenance pages, A/B testing, and geo-based redirects. Using the wrong type negatively impacts SEO rankings.

When should I return 404 vs 410 HTTP status codes?

HTTP 404 Not Found means the resource does not exist but may appear in the future. Search engines retry periodically. HTTP 410 Gone means the resource was intentionally and permanently removed. Search engines remove 410 pages from their index faster. Use 404 for mistyped URLs and broken links. Use 410 for discontinued products and deleted blog posts. For SEO cleanup, 410 more effectively tells search engines to stop crawling specific URLs.

What does HTTP 429 Too Many Requests mean?

HTTP 429 means the client has been rate-limited. The response typically includes a Retry-After header. As a consumer, implement exponential backoff: wait the specified period, then retry with increasing delays. As a provider, return 429 with clear Retry-After headers and document your rate limits. Always respect 429 responses rather than retrying immediately, as aggressive retrying can lead to longer bans or IP blocking.

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