HTTP STATUS CODES

RFC 7231 Standard Reference

1xx Informational

100

Continue

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

Developer Note

Commonly used in large file uploads.

101

Switching Protocols

The requester has asked the server to switch protocols.

Developer Note

Used when upgrading to WebSockets.

102

Processing

Server has received and is processing the request, but no response is available yet.

Developer Note

WebDAV specific.

2xx Success

200

OK

Standard response for successful HTTP requests.

Developer Note

The gold standard for a working endpoint.

201

Created

The request has been fulfilled and has resulted in a new resource being created.

Developer Note

Typical response for a successful POST request.

202

Accepted

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

Developer Note

Used for asynchronous operations.

204

No Content

The server successfully processed the request and is not returning any content.

Developer Note

Common for successful DELETE or PUT updates.

206

Partial Content

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

Developer Note

Used by video players and download managers.

3xx Redirection

301

Moved Permanently

This and all future requests should be directed to the given URI.

Developer Note

Critical for SEO when changing URLs.

302

Found

The resource was found, but at a different URI temporarily.

Developer Note

Temporary redirection.

304

Not Modified

Indicates that the resource has not been modified since the version specified by the request headers.

Developer Note

Key for browser caching and performance.

307

Temporary Redirect

The request should be repeated with another URI; however, future requests should still use the original URI.

Developer Note

Preserves the HTTP method of the original request.

308

Permanent Redirect

The request and all future requests should be repeated using another URI.

Developer Note

Modern alternative to 301 that preserves HTTP method.

4xx Client Error

400

Bad Request

The server cannot or will not process the request due to something that is perceived to be a client error.

Developer Note

Often caused by malformed JSON or invalid parameters.

401

Unauthorized

Similar to 403 Forbidden, but specifically for use when authentication is required and has failed or has not yet been provided.

Developer Note

Check your Bearer tokens or API keys.

403

Forbidden

The request was valid, but the server is refusing action. The user might not have the necessary permissions.

Developer Note

Authenticated but not authorized.

404

Not Found

The requested resource could not be found but may be available in the future.

Developer Note

The most common error on the web.

405

Method Not Allowed

A request method is not supported for the requested resource.

Developer Note

E.g., trying to POST to a GET-only endpoint.

409

Conflict

Indicates that the request could not be processed because of conflict in the current state of the resource.

Developer Note

Common in version control or unique constraint violations.

422

Unprocessable Entity

The request was well-formed but was unable to be followed due to semantic errors.

Developer Note

Standard for validation errors in modern APIs.

429

Too Many Requests

The user has sent too many requests in a given amount of time.

Developer Note

Rate limiting is active.

5xx Server Error

500

Internal Server Error

A generic error message, given when an unexpected condition was encountered and no more specific message is suitable.

Developer Note

The server crashed or hit an unhandled exception.

501

Not Implemented

The server either does not recognize the request method, or it lacks the ability to fulfil the request.

Developer Note

Endpoint is planned but not coded yet.

502

Bad Gateway

The server was acting as a gateway or proxy and received an invalid response from the upstream server.

Developer Note

Common in Nginx/Apache proxy setups.

503

Service Unavailable

The server cannot handle the request (because it is overloaded or down for maintenance).

Developer Note

Use this for planned downtime to help SEO.

504

Gateway Timeout

The server was acting as a gateway or proxy and did not receive a timely response from the upstream server.

Developer Note

Backend is taking too long to process.

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The Definitive HTTP Reference

HTTP response status codes are the foundation of web troubleshooting. Every time you visit a URL or ping an API, the server sends back a status code to tell you how it went. Toolshubkit's Status Code reference provides a comprehensive lookup for all RFC-standard codes, enriched with practical developer notes to help you resolve issues faster.

Official RFC Mapping

Definitions are mapped directly to IETF RFC 7231 specifications, ensuring technical accuracy.

Developer Focused

Beyond dry definitions, we include common causes for errors like 429 Rate Limiting or 504 Timeouts.

SEO Intelligence

Understand how codes like 301 (Permanent) vs 302 (Temporary) impact your search engine rankings.

Mastering Response Classes

1xx Informational

These codes indicate that the request was received and the process is continuing. They are rarely seen in browser interactions but vital for low-level protocol switching like WebSockets.

2xx Success

The gold standard for any API. 200 OK means everything is perfect. 201 Created is the expected response for successful database insertions.

3xx Redirection

Further action must be taken by the user agent to fulfill the request. Use 301 for permanent migration to preserve SEO "link juice."

4xx Client Error

The request contains bad syntax or cannot be fulfilled. 404 is the most famous, but 429 (Too Many Requests) is becoming critical for API stability.

Common Reference Questions

What is the most important SEO code?

The 301 Permanent Redirect. It tells search engines that a page has moved forever, allowing you to transfer ranking power to the new URL.

Difference between 401 and 403?

401 Unauthorized means the server doesn't know who you are. 403 Forbidden means the server knows who you are but you don't have permission for this resource.

Why am I seeing a 502 Bad Gateway?

This usually happens when your proxy server (like Nginx) cannot get a valid response from your application server (like Node.js or Python).

Are these codes case-sensitive?

No. HTTP status codes are three-digit integers. The text descriptions (like 'Not Found') are for human readability and can vary slightly by server.

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Frequently Asked Questions

Everything you need to know about our HTTP Status Codes utility and how we handle your data.

What is a HTTP Status Codes?

Comprehensive developer reference for HTTP status codes with detailed notes and RFC mapping.

How do I use HTTP Status Codes?

Simply input your data into the fields above. Our HTTP Status Codes will process your information instantly. You can then copy the results or export them depending on the specific tool features like Real-time Search or Categorized View.

Is this HTTP Status Codes free?

Yes, the HTTP Status Codes on ToolsHubKit is 100% free to use. we don't require any signup, subscriptions, or hidden fees. It is part of our suite of professional developer utilities designed for the community.

Is my data safe/private?

Your privacy is our primary concern. All processing for the HTTP Status Codes occurs locally within your browser. No data is ever uploaded to our servers or stored in any cloud environment. You can even use this tool offline.

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