HTTP Standing Codes: The Full Checklist

  • January 5, 2023
  • elkenz
  • 13 min read

HTTP standing codes are three-digit numbers included within the server response to let a browser know if its request has been efficiently accomplished. Together with the three-digit quantity, they normally embody an outline of the standing. Specs and their performance are outlined by the World Extensive Internet Consortium (W3C).

The standing codes are how your shopper and a server talk with one another. You’ll be able to view any web page’s HTTP standing codes at no cost utilizing Ahrefs’ web optimization Toolbar by clicking the toolbar icon.

You too can click on and broaden this to see the complete header response, which helps with troubleshooting many technical points.

There are 5 official ranges for the codes:

You may even see some increased codes. These are all unofficial:

Hold studying to study what the standing codes imply and the way Google handles them.

1xxs – Present some sort of extra info

1xx standing codes point out the server has obtained the request and the processing will proceed.

100 Proceed – Every thing is OK proper now. Hold going.

101 Switching Protocols – There’s a message, akin to an improve request, that’s altering issues to a distinct protocol.

102 Processing – Issues are taking place however usually are not achieved but.

103 Early Hints – Allows you to preload assets, which can assist enhance Largest Contentful Paint for Core Internet Vitals.

2xxs – Present {that a} request is profitable

2xx standing codes imply {that a} shopper request has been obtained, understood, and accepted.

200 OK – All good. Every thing is profitable.

201 Created – Much like 200, however the measure of success is {that a} new useful resource has been created.

202 Accepted – A request has been accepted for processing, but it surely hasn’t been accomplished but. It might not have even began but.

203 Non-Authoritative Info – One thing has modified after it was despatched from the server to you.

204 No Content – The request has been despatched, however there’s no content material within the physique.

205 Reset Content – Resets the doc to the unique state, e.g., clearing a type.

206 Partial Content – Solely a few of the content material has been despatched.

207 Multi-Standing – There are extra response codes that may very well be 2xx, 3xx, 4xx, or 5xx.

208 Already Reported – The shopper tells the server the identical useful resource was talked about earlier.

218 That is positive – Unofficial use by Apache.

226 IM Used – This enables the server to ship modifications (diffs) of assets to shoppers.

How Google handles 2xx

Most 2xxs will permit pages to be listed. Nonetheless, 204s will likely be handled as smooth 404s and gained’t be listed.

Gentle 404s can also be URLs the place the server says it’s profitable (200), however the content material of the web page says it doesn’t exist. The code ought to have been a 404, however the server says the whole lot is ok when it isn’t. This may additionally occur on pages with little or no content material.

You will discover these smooth 404 errors within the Protection report in Google Search Console.

Soft 404s excluded in GSC's Coverage report

3xxs – Associated to redirects principally however with few exceptions

3xx standing codes point out the shopper nonetheless must do one thing earlier than the request will be profitable.

300 A number of Selections – There’s multiple doable response, and you’ll have to decide on considered one of them.

301 Moved Completely – The outdated useful resource now redirects to the brand new useful resource.

302 Discovered – The outdated useful resource now redirects to the brand new useful resource briefly.

302 Moved Quickly – The outdated useful resource now redirects to the brand new useful resource briefly.

303 See Different – That is one other redirect that signifies the useful resource could also be discovered someplace else.

304 Not Modified – Says the web page hasn’t been modified. Usually used for caching.

305 Use Proxy – The requested useful resource is just out there in the event you use a proxy.

306 Change Proxy – Your subsequent requests ought to use the proxy specified. This code is now not used.

307 Momentary Redirect – Has the identical performance as a 302 redirect, besides you’ll be able to’t swap between POST and GET.

307 HSTS Coverage – Forces the shopper to make use of HTTPS when making requests as a substitute of HTTP.

308 Everlasting Redirect – Has the identical performance as a 301 redirect, besides you’ll be able to’t swap between POST and GET.

How Google handles 3xx

301s and 302s are canonicalization indicators. They go PageRank and assist decide which URL is proven in Google’s index. A 301 consolidates ahead to the brand new URL, and a 302 consolidates backward to the outdated URL. If a 302 is left in place lengthy sufficient or if the URL it’s redirected to already exists, a 302 could also be handled as a 301 and consolidated ahead as a substitute.

302s can also be used for redirecting customers to language or nation/language-specific homepages, however the identical logic shouldn’t be used for deeper pages.

303s have an undefined therapy from Google. They might be handled as 301 or 302, relying on how they operate.

A 307 has two totally different instances. In instances the place it’s a brief redirect, it will likely be handled the identical as a 302 and try and consolidate backward. When internet servers require shoppers to solely use HTTPS connections (HSTS coverage), Google gained’t see the 307 as a result of it’s cached within the browser. The preliminary hit (with out cache) could have a server response code that’s seemingly a 301 or a 302. However your browser will present you a 307 for subsequent requests.

308s are handled the identical as 301s and consolidate ahead.

Google will comply with as much as 10 hops in a redirect chain. It usually follows 5 hops in a single session and resumes the place it left off within the subsequent session. After this, indicators could not consolidate to the redirected pages.

You will discover these redirect chains in Ahrefs’ Website Audit or our free Ahrefs Webmaster Instruments (AWT).

Redirect chains shown in Ahrefs' Site Audit

4xxs – Errors on the shopper’s aspect

4xx standing codes imply the shopper has an error. The error is normally defined within the response.

400 Unhealthy Request – One thing with the shopper request is mistaken. It’s presumably malformed, invalid, or too massive. And now the server can’t perceive the request.

401 Unauthorized – The shopper hasn’t recognized or verified itself when wanted.

402 Cost Required – This doesn’t have an official use, and it’s reserved for the long run for some sort of digital fee system. Some retailers use this for their very own causes, e.g., Shopify makes use of this when a retailer hasn’t paid its charges, and Stripe makes use of this for probably fraudulent funds.

403 Forbidden – The shopper is understood however doesn’t have entry rights.

404 Not Discovered – The requested useful resource isn’t discovered.

405 Methodology Not Allowed – The request methodology used isn’t supported, e.g., a type wants to make use of POST however makes use of GET as a substitute.

406 Not Acceptable – The settle for header requested by the shopper can’t be fulfilled by the server.

407 Proxy Authentication Required – The authentication must be achieved by way of proxy.

408 Request Timeout – The server has timed out or determined to shut the connection.

409 Battle – The request conflicts with the state of the server.

410 Gone – Much like a 404 the place the request isn’t discovered, however this additionally says it gained’t be out there once more.

411 Size Required – The request doesn’t include a content-length discipline when it’s required.

412 Precondition Failed – The shopper places a situation on the request that the server doesn’t meet.

413 Payload Too Massive – The request is bigger than what the server permits.

414 URI Too Lengthy – The URI requested is longer than the server permits.

415 Unsupported Media Sort – The format requested isn’t supported by the server.

416 Vary Not Satisfiable – The shopper asks for a portion of the file that may’t be provided by the server, e.g., it asks for part of the file past the place the file truly ends.

417 Expectation Failed – The expectation indicated within the “Count on” request header can’t be met by the server.

418 I’m a Teapot – Occurs while you attempt to brew espresso in a teapot. This began as an April Idiot’s joke in 1998 however is definitely standardized. With the whole lot being good gadgets nowadays, this might probably be used.

419 Web page Expired – Unofficial use by Laravel Framework.

420 Methodology Failure – Unofficial use by Spring Framework.

420 Improve Your Calm – Unofficial use by Twitter.

421 Misdirected Request – The server {that a} request was despatched to can’t reply to it.

422 Unprocessable Entity – There are semantic errors within the request.

423 Locked – The requested useful resource is locked.

424 Failed Dependency – This failure occurs as a result of it wants one other request that additionally failed.

425 Too Early – The server is unwilling to course of the request presently as a result of the request is prone to come once more later.

426 Improve Required – The server refuses the request till the shopper makes use of a more moderen protocol. What must be upgraded is indicated within the “Improve” header.

428 Precondition Required – The server requires the request to be conditional.

429 Too Many Requests – It is a type of rate-limiting to guard the server as a result of the shopper despatched too many requests to the server too quick.

430 Request Header Fields Too Massive – Unofficial use by Shopify.

431 Request Header Fields Too Massive – The server gained’t course of the request as a result of the header fields are too massive.

440 Login Time-out – Unofficial use by IIS.

444 No Response – Unofficial use by nginx.

449 Retry With – Unofficial use by IIS.

450 Blocked by Home windows Parental Controls – Unofficial use by Microsoft.

451 Unavailable For Authorized Causes – That is blocked for some sort of authorized cause. You’ll see it typically with country-level blocks, e.g., blocked information or movies, on account of privateness or licensing. You may even see it for DMCA takedowns. The code itself is a reference to the novel Fahrenheit 451.

451 Redirect – Unofficial use by IIS.

460 – Unofficial use by AWS Elastic Load Balancer.

463 – Unofficial use by AWS Elastic Load Balancer.

494 Request header too massive – Unofficial use by nginx.

495 SSL Certificates Error – Unofficial use by nginx.

496 SSL Certificates Required – Unofficial use by nginx.

497 HTTP Request Despatched to HTTPS Port – Unofficial use by nginx.

498 Invalid Token – Unofficial use by Esri.

499 Consumer Closed Request – Unofficial use by nginx.

499 Token Required – Unofficial use by Esri.

How Google handles 4xx

4xxs will trigger pages to drop from the index.

404s and 410s have the same therapy. Each drop pages from the index, however 410s are barely quicker. In sensible functions, they’re roughly the identical.

421s are utilized by Google to decide out of crawling with HTTP/2.

429s are a bit particular as a result of they’re typically handled as server errors and can trigger Google to decelerate crawling. However ultimately, Google will drop these pages from the index as nicely.

You will discover 4xx errors in Website Audit or our free Ahrefs Webmaster Instruments.

Pie chart showing HTTP status codes distribution

One other factor chances are you’ll need to examine is that if any of those 404 pages have hyperlinks to them. If the hyperlinks level to a 404 web page, they don’t depend in your web site. Greater than seemingly, you simply have to 301 redirect every of those pages to a related web page.

Right here’s the right way to discover these alternatives:

  1. Paste your area into Website Explorer (additionally accessible at no cost in AWT)
  2. Go to the Greatest by hyperlinks report
  3. Add a “404 not discovered” HTTP response filter

I normally type this by “Referring domains.”

404s with links in the Best by links report that you can redirect

5xx standing codes imply the server has an error, and it is aware of it could’t perform the request. The response will include a cause for the error.

500 Inside Server Error – The server encounters some sort of concern and doesn’t have a greater or extra particular error code.

501 Not Carried out – The request methodology isn’t supported by the server.

502 Unhealthy Gateway – The server was in the course of a request and used for routing. But it surely has obtained a nasty response from the server it was routing to.

503 Service Unavailable – The server is overloaded or down for upkeep and might’t deal with the request proper now. It’ll in all probability be again up quickly.

504 Gateway Timeout – The server was in the course of a request and used for routing. But it surely has not obtained a well timed response from the server it was routing to.

505 HTTP Model Not Supported – That is precisely what it says: The HTTP protocol model within the request isn’t supported by the server.

506 Variant Additionally Negotiates – Permits the shopper to get the most effective variant of a useful resource when the server has a number of variants.

507 Inadequate Storage – The server can’t retailer what it must retailer to finish the request.

508 Loop Detected – The server discovered an infinite loop when attempting to course of the request.

509 Bandwidth Restrict Exceeded – Unofficial use by Apache and cPanel.

510 Not Prolonged – Extra extensions to the request are required earlier than the server will fulfill it.

511 Community Authentication Required – The shopper wants authentication earlier than the server permits community entry.

520 Internet Server Returned an Unknown Error – Unofficial use by Cloudflare.

521 Internet Server is Down – Unofficial use by Cloudflare.

522 Connection Timed Out – Unofficial use by Cloudflare.

523 Origin is Unreachable – Unofficial use by Cloudflare.

524 A Timeout Occurred – Unofficial use by Cloudflare.

525 SSL Handshake Failed – Unofficial use by Cloudflare.

526 Invalid SSL Certificates – Unofficial use by Cloudflare.

527 Railgun Error – Unofficial use by Cloudflare.

529 Website is overloaded – Unofficial use by Qualys.

530 – Unofficial use by Cloudflare.

530 Website is frozen – Unofficial use by Pantheon.

561 Unauthorized – Unofficial use by AWS Elastic Load Balancer.

598 (Casual conference) Community learn timeout error – Unofficial use by some HTTP proxies.

How Google handles 5xx

5xx errors will decelerate crawling. Finally, the pages will likely be dropped from Google’s index. You will discover these in Website Audit or Ahrefs Webmaster Instruments, however they might be totally different from the 5xxs that Google sees. Since these are server errors, they might not at all times be current.

4xx and 5xx errors in Ahrefs' Site Audit

The requirements solely specify 1xx-5xx codes, however chances are you’ll encounter some unofficial standing codes. Plenty of instances these will likely be utilized by totally different platforms or they might permit customers to make use of sure ranges for any customized codes. As a result of these are all customized, it could be unimaginable to record what they do. The numbers can go above 1,000.


999 – That is widespread sufficient to say. It’s normally a generic error code used when a request is unable to be processed or it’s denied.