Free HTTP Status Codes Reference
Every HTTP status code explained — searchable reference for 1xx, 2xx, 3xx, 4xx, and 5xx responses.
How it works
Search or browse
Type a code number or keyword to filter. Or browse by category (2xx, 4xx, etc.).
Read the explanation
Each code shows the official name and a plain-English description.
Click for details
Click any row to expand for use-case context and common causes.
No code needed
This is a static reference — no processing, just fast search.
Common use cases
API design
Choose the most semantically correct status code for each API endpoint response.
Debugging
Quickly look up what a status code from a server log or error response means.
Code review
Verify that developers are returning appropriate status codes for success, validation errors, and not-found cases.
Learning HTTP
Browse all status codes with descriptions to understand the full range of HTTP responses.
Frequently asked questions
What is the difference between 401 and 403?
401 means "you are not authenticated — please log in." 403 means "you are authenticated but not allowed to access this." Think of it as: 401 = who are you? 403 = I know who you are, but no.
When should I use 404 vs 410?
Use 404 when you don't know if the resource ever existed or might return. Use 410 when the resource is permanently gone and will never come back — search engines will remove it faster.
What is the difference between 301 and 302?
301 is permanent redirect — search engines and browsers cache it and update bookmarks. 302 is temporary — the original URL may work again later, so don't cache it permanently.
When should I use 422 vs 400?
400 (Bad Request) for malformed syntax — the server can't parse the request. 422 (Unprocessable Content) for valid syntax but invalid semantics — the server parsed it but the field values are wrong.