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HTTP Status Code Lookup

Fast reference library for 1xx, 2xx, 3xx, 4xx, and 5xx HTTP response status codes with explanations and use cases.

Showing 30 HTTP status codes
100

Continue

The server has received the request headers and the client should proceed to send the request body.

Typical Use Case: Sent in response to an Expect: 100-continue request header before uploading large payloads.
Specification: RFC 9110 §15.2.1
101

Switching Protocols

The requester has asked the server to switch protocols and the server has agreed to do so.

Typical Use Case: Upgrading an HTTP/1.1 connection to a WebSocket connection.
Specification: RFC 9110 §15.2.2
103

Early Hints

Used to return headers before the final HTTP message to allow preloading critical assets.

Typical Use Case: Link preload headers for CSS or fonts before the server completes rendering the HTML response.
Specification: RFC 8297
200

OK

The request has succeeded. The information returned with the response depends on the method used.

Typical Use Case: Standard successful response for GET, POST, or PUT requests.
Specification: RFC 9110 §15.3.1
201

Created

The request has been fulfilled, resulting in the creation of a new resource.

Typical Use Case: Response to a POST request creating a new user, order, or record in a database.
Specification: RFC 9110 §15.3.2
202

Accepted

The request has been accepted for processing, but the processing has not been completed.

Typical Use Case: Asynchronous job queues, background batch processing, or video transcoding.
Specification: RFC 9110 §15.3.3
204

No Content

The server has successfully fulfilled the request and there is no additional content to send in the response payload.

Typical Use Case: Successful DELETE request, or a save action where the client does not need an updated representation.
Specification: RFC 9110 §15.3.5
206

Partial Content

The server is delivering only part of the resource due to a Range header sent by the client.

Typical Use Case: Resumable downloads, video/audio streaming with byte-range requests.
Specification: RFC 9110 §15.3.7
301

Moved Permanently

The target resource has been assigned a new permanent URI and any future references should use one of the returned URIs.

Typical Use Case: Permanent domain migration, redirecting HTTP to HTTPS, or permanent URL restructuring for SEO.
Specification: RFC 9110 §15.4.2
302

Found (Temporary Redirect)

The target resource resides temporarily under a different URI. Browsers often incorrectly change POST to GET.

Typical Use Case: Temporary maintenance redirects or redirecting after login.
Specification: RFC 9110 §15.4.3
304

Not Modified

Indicates that the resource has not been modified since the version specified by the request headers If-Modified-Since or If-None-Match.

Typical Use Case: Browser caching validation with ETags. Saves bandwidth by avoiding re-downloading static assets.
Specification: RFC 9110 §15.4.5
307

Temporary Redirect

The target resource resides temporarily under a different URI and the user agent MUST NOT change the request method.

Typical Use Case: Temporary redirect of a POST form submission where the method and body must be preserved.
Specification: RFC 9110 §15.4.8
308

Permanent Redirect

The target resource has been assigned a new permanent URI and the request method MUST NOT change.

Typical Use Case: Permanent redirect of API POST/PUT endpoints where preserving the HTTP method is required.
Specification: RFC 9110 §15.4.9
400

Bad Request

The server cannot or will not process the request due to something perceived to be a client error (e.g. malformed syntax, invalid framing).

Typical Use Case: Malformed JSON payload, invalid query parameter types, or missing required headers.
Specification: RFC 9110 §15.5.1
401

Unauthorized

The request has not been applied because it lacks valid authentication credentials for the target resource.

Typical Use Case: Missing or expired JWT bearer token, or incorrect API key.
Specification: RFC 9110 §15.5.2
403

Forbidden

The server understood the request but refuses to authorize it. Unlike 401, re-authenticating will not help if permissions are lacking.

Typical Use Case: A standard user trying to access an admin-only endpoint, or IP blacklist restrictions.
Specification: RFC 9110 §15.5.4
404

Not Found

The origin server did not find a current representation for the target resource or is not willing to disclose that one exists.

Typical Use Case: Requesting a nonexistent page, missing product ID, or deleted file.
Specification: RFC 9110 §15.5.5
405

Method Not Allowed

The method received in the request-line is known by the server but not supported by the target resource.

Typical Use Case: Sending a POST request to a route that only supports GET.
Specification: RFC 9110 §15.5.6
408

Request Timeout

The server did not receive a complete request message within the time that it was prepared to wait.

Typical Use Case: Slow client connection dropping midway through uploading data.
Specification: RFC 9110 §15.5.9
409

Conflict

The request could not be completed due to a conflict with the current state of the target resource.

Typical Use Case: Attempting to create an account with an email that already exists, or edit collisions in version control.
Specification: RFC 9110 §15.5.10
410

Gone

The target resource is no longer available at the origin server and no forwarding address is known.

Typical Use Case: Purposely deleted promotional pages or sunset API endpoints.
Specification: RFC 9110 §15.5.11
413

Payload Too Large

The server is refusing to process a request because the request payload is larger than the server is willing or able to process.

Typical Use Case: Uploading an image or file exceeding the server limit (e.g. over 10MB).
Specification: RFC 9110 §15.5.14
415

Unsupported Media Type

The origin server is refusing to service the request because the payload format is in an unsupported format.

Typical Use Case: Sending XML to an endpoint that only accepts Content-Type: application/json.
Specification: RFC 9110 §15.5.16
422

Unprocessable Content

The server understands the content type of the request entity, and the syntax is correct, but was unable to process the contained instructions.

Typical Use Case: Validation failure (e.g. password too short, age must be a positive number).
Specification: RFC 9110 §15.5.21
429

Too Many Requests

The user has sent too many requests in a given amount of time (rate limiting).

Typical Use Case: API rate limiting with Retry-After response headers.
Specification: RFC 6585
500

Internal Server Error

The server encountered an unexpected condition that prevented it from fulfilling the request.

Typical Use Case: Unhandled exception in backend code, database connection failure, or fatal runtime crash.
Specification: RFC 9110 §15.6.1
501

Not Implemented

The server does not support the functionality required to fulfill the request.

Typical Use Case: Server does not recognize the request method (e.g. PATCH on an older legacy server).
Specification: RFC 9110 §15.6.2
502

Bad Gateway

The server, while acting as a gateway or proxy, received an invalid response from an inbound server it accessed.

Typical Use Case: Nginx or Cloudflare unable to communicate with the Node.js or Python upstream server.
Specification: RFC 9110 §15.6.3
503

Service Unavailable

The server is currently unable to handle the request due to temporary overloading or maintenance of the server.

Typical Use Case: Scheduled maintenance or peak traffic exhaustion.
Specification: RFC 9110 §15.6.4
504

Gateway Timeout

The server, while acting as a gateway or proxy, did not receive a timely response from an upstream server.

Typical Use Case: Proxy timing out while waiting for a heavy database query or external API call to finish.
Specification: RFC 9110 §15.6.5

How to Use HTTP Status Code Lookup

01

Search by Number or Keyword

Enter any status number (e.g. 404, 502) or keywords like 'unauthorized', 'gateway', or 'conflict'.

02

Filter by Status Class

Click category pills (2xx Success, 4xx Client Error, 5xx Server Error) to view specific ranges.

03

Inspect Specs & Use Cases

Review typical real-world developer scenarios and official RFC standards for each status.

Key Capabilities

RFC 9110 Compliant

Direct references to the latest HTTP standard specifications.

Visual Color Coding

Clear visual hierarchy distinguishing success, redirects, and error codes.

Instant Search

Blazing fast client-side indexing finds relevant codes on the first keystroke.

Developer Scenarios

Contains practical guidance for API design and error handling.

Related Tools

Frequently used companion utilities for this workflow