HTTP Status Reference

Continue

The server received the request headers and the client should proceed.

Switching Protocols

Upgrading to a different protocol (e.g. WebSocket).

Early Hints

Preloads Link headers before the final response.

💡 Great for pushing fonts / critical CSS.

OK

Standard success. The response body is meaningful.

💡 GET, HEAD — anything worked.

Created

Resource was created successfully.

💡 Return after POST /things.

Accepted

Accepted for processing but not completed yet.

💡 Async workflows.

No Content

Success, no body. Common for DELETE.

💡 Return for PUTs without a meaningful body.

Partial Content

Byte-range response (video streaming, resumable downloads).

Moved Permanently

Permanent redirect, cached by search engines.

💡 Use only when the move is definitively final.

Found

Temporary redirect — caches expire quickly.

See Other

Redirect with a GET, typical after POST/Redirect/GET.

Not Modified

Cached resource is still fresh — no body.

💡 Pair with ETag / If-None-Match.

Temporary Redirect

Same as 302 but preserves the HTTP method.

Permanent Redirect

Same as 301 but preserves the method.

Bad Request

Malformed request — JSON error, missing field, etc.

Unauthorized

Auth is required and either missing or invalid.

💡 Expect a WWW-Authenticate header.

Payment Required

Reserved historically; used by some APIs for quota / billing errors.

💡 We use this for insufficient credits.

Forbidden

Authenticated but not allowed.

💡 Use when identity is known but role lacks permission.

Not Found

Resource does not exist.

Method Not Allowed

The resource exists but the method is wrong.

💡 Include Allow: header.

Conflict

Update conflicts with current state (e.g. optimistic lock failure).

💡 Great for unique-constraint violations.

Gone

Resource was here but is permanently removed.

Payload Too Large

Request body exceeds server limits.

Unsupported Media Type

Content-Type isn't supported by the endpoint.

I'm a teapot

RFC 2324 April Fools joke. Surprisingly still widely deployed.

Unprocessable Entity

Syntactically OK but semantically invalid (validation errors).

Precondition Required

Server requires conditional headers to prevent lost updates.

Too Many Requests

Rate limited — include Retry-After.

Unavailable For Legal Reasons

Blocked due to a legal demand (Fahrenheit 451 reference).

Internal Server Error

Generic server-side error catch-all.

Not Implemented

The method is not supported at all on this server.

Bad Gateway

Upstream server returned an invalid response.

Service Unavailable

Server overloaded or down for maintenance.

💡 Use Retry-After for scheduled downtime.

Gateway Timeout

Upstream server didn't reply in time.

Insufficient Storage

Server has no room to store the representation.

Network Authentication Required

Captive portal — auth needed before network access.