HTTP status codes

Search and reference table (1xx–5xx)

All computation runs locally in your browser

Last updated: February 4, 2026

CreatorFrank Zhao

Showing 63 status codes

1xx informational response

4 codes

100 Continue

Waiting for the client to emit the body of the request.

HTTP

101 Switching Protocols

The server has agreed to change protocol.

HTTP

102 Processing

The server is processing the request, but no response is available yet.

WebDav

103 Early Hints

The server returns some response headers before final HTTP message.

HTTP

2xx success

10 codes

200 OK

Standard response for successful HTTP requests.

HTTP

201 Created

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

HTTP

202 Accepted

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

HTTP

203 Non-Authoritative Information

The request is successful but the content of the original request has been modified by a transforming proxy.

HTTP

204 No Content

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

HTTP

205 Reset Content

The server indicates to reinitialize the document view which sent this request.

HTTP

206 Partial Content

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

HTTP

207 Multi-Status

The message body that follows is an XML message and can contain a number of separate response codes.

WebDav

208 Already Reported

The members of a DAV binding have already been enumerated in a preceding part of the (multistatus) response.

WebDav

226 IM Used

The server has fulfilled a request for the resource, and the response is a representation of the result.

HTTP

3xx redirection

9 codes

300 Multiple Choices

Indicates multiple options for the resource that the client may follow.

HTTP

301 Moved Permanently

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

HTTP

302 Found

Redirect to another URL. This is an example of industry practice contradicting the standard.

HTTP

303 See Other

The response to the request can be found under another URI using a GET method.

HTTP

304 Not Modified

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

HTTP

305 Use Proxy

The requested resource is available only through a proxy, the address for which is provided in the response.

HTTP

306 Switch Proxy

No longer used. Originally meant "Subsequent requests should use the specified proxy."

HTTP

307 Temporary Redirect

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

HTTP

308 Permanent Redirect

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

HTTP

4xx client error

29 codes

400 Bad Request

The server cannot or will not process the request due to an apparent client error.

HTTP

401 Unauthorized

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

HTTP

402 Payment Required

Reserved for future use. The original intention was that this code might be used as part of some form of digital cash or micropayment scheme.

HTTP

403 Forbidden

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

HTTP

404 Not Found

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

HTTP

405 Method Not Allowed

A request method is not supported for the requested resource.

HTTP

406 Not Acceptable

The requested resource is capable of generating only content not acceptable according to the Accept headers sent in the request.

HTTP

407 Proxy Authentication Required

The client must first authenticate itself with the proxy.

HTTP

408 Request Timeout

The server timed out waiting for the request.

HTTP

409 Conflict

Indicates that the request could not be processed because of conflict in the request, such as an edit conflict.

HTTP

410 Gone

Indicates that the resource requested is no longer available and will not be available again.

HTTP

411 Length Required

The request did not specify the length of its content, which is required by the requested resource.

HTTP

412 Precondition Failed

The server does not meet one of the preconditions that the requester put on the request.

HTTP

413 Payload Too Large

The request is larger than the server is willing or able to process.

HTTP

414 URI Too Long

The URI provided was too long for the server to process.

HTTP

415 Unsupported Media Type

The request entity has a media type which the server or resource does not support.

HTTP

416 Range Not Satisfiable

The client has asked for a portion of the file, but the server cannot supply that portion.

HTTP

417 Expectation Failed

The server cannot meet the requirements of the Expect request-header field.

HTTP

418 I'm a teapot

The server refuses the attempt to brew coffee with a teapot.

HTTP

421 Misdirected Request

The request was directed at a server that is not able to produce a response.

HTTP

422 Unprocessable Entity

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

HTTP

423 Locked

The resource that is being accessed is locked.

HTTP

424 Failed Dependency

The request failed due to failure of a previous request.

HTTP

425 Too Early

Indicates that the server is unwilling to risk processing a request that might be replayed.

HTTP

426 Upgrade Required

The client should switch to a different protocol such as TLS/1.0.

HTTP

428 Precondition Required

The origin server requires the request to be conditional.

HTTP

429 Too Many Requests

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

HTTP

431 Request Header Fields Too Large

The server is unwilling to process the request because either an individual header field, or all the header fields collectively, are too large.

HTTP

451 Unavailable For Legal Reasons

A server operator has received a legal demand to deny access to a resource or to a set of resources that includes the requested resource.

HTTP

5xx server error

11 codes

500 Internal Server Error

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

HTTP

501 Not Implemented

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

HTTP

502 Bad Gateway

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

HTTP

503 Service Unavailable

The server is currently unavailable (because it is overloaded or down for maintenance).

HTTP

504 Gateway Timeout

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

HTTP

505 HTTP Version Not Supported

The server does not support the HTTP protocol version used in the request.

HTTP

506 Variant Also Negotiates

Transparent content negotiation for the request results in a circular reference.

HTTP

507 Insufficient Storage

The server is unable to store the representation needed to complete the request.

HTTP

508 Loop Detected

The server detected an infinite loop while processing the request.

HTTP

510 Not Extended

Further extensions to the request are required for the server to fulfill it.

HTTP

511 Network Authentication Required

The client needs to authenticate to gain network access.

HTTP

HTTP status codes are the fastest way to understand what happened in a request: success, redirect, authentication issues, rate limits, or server failures. This guide explains how to read the codes, how to troubleshoot common ones, and how to share a filtered view of the table.

→Introduction / overview
→How to Use / Quick Start
→Real-World Examples
→Common Scenarios
→Tips & Best Practices
→Calculation Method
→Related Concepts
→Frequently Asked Questions
→Limitations / Disclaimers
→External References

Introduction / overview

The HTTP Status Codes tool is a searchable reference for the most common HTTP and WebDAV status codes. It helps you answer questions like: “Is this failure on the client or server?”, “Should I retry?”, or “Is this a redirect or a cache hit?”.

A practical way to use status codes: treat them as a short, standardized summary of the outcome. Start with the first digit (class), then read the specific code for details.

Who uses this most?

Developers debugging APIs, proxies, CDNs, and browser network calls.
DevOps/SRE teams triaging incidents with logs, metrics, and tracing.
QA and product teams validating integrations and edge cases.

Privacy note: this page is a static reference and search runs locally in your browser.

If you are working on authentication and repeatedly hit $401$ or $403$ , it often helps to cross-check your headers using Basic auth generator. For URL issues, pair it with URL parser.

How to Use / Quick Start Guide

Type a code or keyword

Use the search box to filter by code (404), name (Not Found), description, or type (WebDAV).

Scan the category heading

The category (1xx–5xx) quickly tells you whether it is informational, success, redirect, client error, or server error.

Open Share to copy a link

Use Share to get a URL. If you searched for something, the shared link can include your query so teammates see the same filtered view.

Worked example: quick incident triage

You watch a dashboard and see $N=120$ requests in a minute. $N_{5xx}=9$ are server errors. A quick way to summarize the impact is the 5xx error rate:

r_{5xx}

=

\frac{N_{5xx}}{N}\cdot 100\%

=

\frac{9}{120}\cdot 100\%

=

7.5\%

Now you can say: “We are at $7.5\%$ 5xx right now” and then use the table to check the specific code (for example $502$ vs $503$ ) to choose the next step.

Worked example: success vs redirect

Suppose a client made $N=200$ requests. You logged $N_{2xx}=160$ successes and $N_{3xx}=30$ redirects. The success rate is:

r_{2xx}

=

\frac{N_{2xx}}{N}\cdot 100\%

=

\frac{160}{200}\cdot 100\%

=

80\%

Redirects can be fine (for example HTTP to HTTPS migrations). But if $3xx$ suddenly spikes, look for broken caching rules, incorrect canonical URLs, or a misconfigured reverse proxy.

Real-World Examples / Use Cases

502 / 504 behind a reverse proxy

Background: A service works locally, but traffic through a proxy returns $502$ .

Inputs: status code $502$ , request path, upstream timeout settings.

Result: use the description to confirm this is usually an upstream issue, then check proxy logs and timeouts.

401 vs 403 in API auth

Background: Requests fail after adding auth headers.

Inputs: status $401$ or $403$ , auth method, and headers.

How to apply: $401$ often means missing or invalid credentials; $403$ often means authenticated but not allowed. If you use Basic Auth, generate a correct header with Basic auth generator.

304 Not Modified and caching sanity checks

Background: A page looks stale, but requests return $304$ .

Inputs: status $304$ , cache headers, ETag, and browser reload mode.

Result: confirm the server is telling the client to reuse cached content; then verify cache-control rules.

429 rate limiting during load tests

Background: A test starts failing with $429$ .

Inputs: request rate, retry policy, and any Retry-After headers.

How to apply: reduce concurrency, implement exponential backoff, or request higher limits.

Common Scenarios / When to Use

API development

Quickly confirm what a response code means while building endpoints or clients.

Log review

Translate a wall of 4xx/5xx into clear next actions: fix client inputs, permissions, or server health.

Retry decisions

Decide whether a request should be retried (timeouts, 5xx) or fixed (validation errors, 4xx).

Incident triage

During an outage, quickly communicate the meaning of the dominant status code to stakeholders.

Auth troubleshooting

Differentiate between “not logged in” and “not allowed” using 401/403 as the starting point.

Proxy and CDN debugging

Explain 301/302 loops, 304 caching behavior, and gateway errors like 502/504.

When it may not be enough: status codes alone do not explain what data failed validation or which upstream system timed out. Pair them with logs, trace IDs, and response bodies.

Tips & Best Practices

Start with the first digit

If you only remember one thing: $4xx$ is usually a client-side issue (inputs, auth, permissions), and $5xx$ is usually a server-side issue (upstream, overload, crash).

Retry with intention

Retrying a $429$ or $503$ without backoff can make things worse. Prefer exponential backoff and respect Retry-After when present.

Share the exact filter when collaborating

If your team is discussing one code family (for example WebDAV), use Share after searching so everyone lands on the same filtered view.

Calculation Method / Formula Explanation

This tool is primarily a reference table (it does not compute responses for you), but teams often use status code counts to summarize behavior.

r_{kxx} = \frac{N_{kxx}}{N}\cdot 100\%

where $k \in \{2,3,4,5\}$ for the status code family.

Variables explained

$N$ = total number of responses in your time window
$N_{kxx}$ = number of responses in the $kxx$ family
$r_{kxx}$ = percentage rate for that family

Related Concepts / Background Info

Families matter

Codes are grouped by their first digit: $1xx$ informational, $2xx$ success, $3xx$ redirection, $4xx$ client error, and $5xx$ server error.

Caching is not always obvious

A $304$ can be a good sign (cache working) or a confusing one (stale content). Always interpret it alongside response headers.

If you are debugging URL formatting issues that trigger unexpected $400$ or $404$ , try the URL encoder and URL parser.

Frequently Asked Questions (FAQs)

Is 404 always a broken link?

Not always. A $404$ means the server did not find the resource. It can be a broken route, a missing file, a wrong hostname, or even an intentionally hidden endpoint.

When should I retry a request?

Retrying is most reasonable for transient failures like $408$ , $429$ (with backoff), and some $5xx$ responses. Retrying most $4xx$ responses without changing the request usually does not help.

What is the difference between 401 and 403?

$401$ means authentication is missing or failed. $403$ means you are authenticated (or identified) but do not have permission.

Is 204 an error?

No. $204$ is a success status that intentionally returns no body. It is common for “delete” operations or “save” endpoints.

Why do I see 102 or 207?

Those are commonly associated with WebDAV. This tool includes both HTTP and WebDAV codes so you can interpret responses from file servers and collaboration platforms.

Limitations / Disclaimers

Status codes are only one part of debugging. They do not replace reading the response body, request logs, server metrics, or tracing data.

This reference is informational. It does not provide legal, compliance, or security advice.

External References / Sources

Standards and references

If you frequently copy headers, tokens, and URLs while debugging, you may also like JWT parser, URL encoder, and MIME types.

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