Returning a 200 for errors, using 401 when you mean 403, or sending 500 for validation failures — these status code mistakes confuse API consumers and break client-side error handling. Using the right status code communicates intent clearly and follows REST conventions.
What Is HTTP Status Codes?
HTTP status codes are three-digit numbers in API responses that indicate the result of a request. They're grouped: 2xx (success), 3xx (redirection), 4xx (client error), 5xx (server error). Our HTTP Status Codes reference explains each code with examples.
How to Use HTTP Status Codes on DevToolHub
- Open the HTTP Status Codes tool on DevToolHub — no signup required.
- Paste or enter your input data in the left panel.
- See the result instantly in the output panel.
- Copy the result or download it as a file.
Most Important Status Codes
The ones you'll use in 90% of APIs:
// Success
200 OK — Request succeeded, response has data
201 Created — Resource created (POST/PUT)
204 No Content — Success, no response body (DELETE)
// Redirection
301 Moved Permanently — URL changed forever (SEO redirect)
304 Not Modified — Use cached version
// Client Error
400 Bad Request — Invalid input/validation error
401 Unauthorized — Authentication required
403 Forbidden — Authenticated but not allowed
404 Not Found — Resource doesn't exist
409 Conflict — Duplicate resource
429 Too Many Requests — Rate limited
// Server Error
500 Internal Server Error — Unexpected server failure
503 Service Unavailable — Server overloaded/maintenancePro Tips
- Use 401 for 'who are you?' and 403 for 'you can't do that' — they're different!
- Return 404 for missing resources and 400 for invalid input — don't use 404 for validation
- 429 should include a Retry-After header telling the client when to try again
- Never return 200 with an error message in the body — use proper 4xx/5xx codes
When You Need This
- Designing REST API response status codes correctly
- Debugging API errors by understanding status code meanings
- Building proper error handling in frontend applications
- Writing API documentation with correct status code descriptions
Free Tools Mentioned in This Article