Ever stumbled upon a ‘404 Not Found’ page and wondered what on earth it means? You’re not alone. These numbers are called HTTP status codes, and they’re basically short messages from a server telling your browser how its request went. Think of it as a quick “OK, all good!” or a “Sorry, can’t find that!” from the website you’re trying to visit.
Understanding this list of HTTP status codes is super useful, especially if you run a website and want to keep it in tip-top shape for your visitors and for search engines like Google.
1xx Informational Responses
This class of status code indicates that the request was received and the process is continuing.
- 100 Continue: The server has received the request headers, and the client should proceed to send the request body.
- 101 Switching Protocols: The requester has asked the server to switch protocols, and the server has agreed to do so.
- 102 Processing (WebDAV): The server has received and is processing the request, but no response is available yet.
- 103 Early Hints: Used to return some response headers before the final HTTP message.
2xx Successful Responses
This class of status codes indicates the action requested by the client was received, understood, and accepted successfully.
- 200 OK: The request has succeeded. The meaning of a “success” varies depending on the HTTP method.
- 201 Created: The request has been fulfilled and has resulted in one or more new resources being created.
- 202 Accepted: The request has been accepted for processing, but the processing has not been completed.
- 203 Non-Authoritative Information: The returned meta-information is from a local or third-party copy, not from the original server.
- 204 No Content: The server successfully processed the request and is not returning any content.
- 205 Reset Content: The server successfully processed the request, but is not returning any content and requires that the requester reset the document view.
- 206 Partial Content: The server is delivering only part of the resource due to a range header sent by the client.
- 207 Multi-Status (WebDAV): The message body that follows is an XML message and can contain a number of separate response codes.
- 208 Already Reported (WebDAV): The members of a DAV binding have already been enumerated in a preceding part of the response.
- 226 IM Used (HTTP Delta encoding): The server has fulfilled a request for the resource, and the response is a representation of the result of one or more instance-manipulations applied to the current instance.
3xx Redirection Messages
This class of status code indicates that further action needs to be taken by the user agent in order to fulfil the request.
- 300 Multiple Choices: The request has more than one possible response.
- 301 Moved Permanently: This and all future requests should be directed to the given URI.
- 302 Found: This is a temporary redirect. The client should continue to use the original URI for future requests.
- 303 See Other: The response to the request can be found under another URI using a GET method.
- 304 Not Modified: Indicates the resource has not been modified since the version specified by the request headers.
- 305 Use Proxy (Deprecated): The requested resource is available only through a proxy.
- 306 Switch Proxy (Deprecated): No longer used.
- 307 Temporary Redirect: The request should be repeated with another URI, but future requests should still use the original URI.
- 308 Permanent Redirect: The request and all future requests should be repeated using another URI.
4xx Client Error Responses
This class of status code is intended for situations in which the error seems to have been caused by the client.
- 400 Bad Request: The server cannot or will not process the request due to something that is perceived to be a client error.
- 401 Unauthorized: The client must authenticate itself to get the requested response.
- 402 Payment Required: Reserved for future use.
- 403 Forbidden: The client does not have access rights to the content.
- 404 Not Found: The server can’t find the requested resource.
- 405 Method Not Allowed: The request method is known by the server but is not supported by the target resource.
- 406 Not Acceptable: The server cannot produce a response matching the list of acceptable values defined in the request’s proactive content negotiation headers.
- 407 Proxy Authentication Required: The client must first authenticate itself with the proxy.
- 408 Request Timeout: The server would like to shut down this unused connection.
- 409 Conflict: The request could not be completed due to a conflict with the current state of the resource.
- 410 Gone: The requested content has been permanently deleted from the server.
- 411 Length Required: The server rejected the request because the Content-Length header field is not defined and the server requires it.
- 412 Precondition Failed: The client has indicated preconditions in its headers which the server does not meet.
- 413 Payload Too Large: Request entity is larger than limits defined by the server.
- 414 URI Too Long: The URI requested by the client is longer than the server is willing to interpret.
- 415 Unsupported Media Type: The media format of the requested data is not supported by the server.
- 416 Range Not Satisfiable: The range specified by the Range header field in the request can’t be fulfilled.
- 417 Expectation Failed: The expectation indicated by the Expect request header field could not be met by the server.
- 418 I’m a teapot: The server refuses to brew coffee because it is, permanently, a teapot. (An April Fools’ joke RFC).
- 421 Misdirected Request: The request was directed at a server that is not able to produce a response.
- 422 Unprocessable Entity (WebDAV): The request was well-formed but could not be followed due to semantic errors.
- 423 Locked (WebDAV): The resource that is being accessed is locked.
- 424 Failed Dependency (WebDAV): The request failed due to failure of a previous request.
- 425 Too Early (Experimental): Indicates that the server is unwilling to risk processing a request that might be replayed.
- 426 Upgrade Required: The server refuses to perform the request using the current protocol but might be willing to do so after the client upgrades to a different protocol.
- 428 Precondition Required: The origin server requires the request to be conditional.
- 429 Too Many Requests: The user has sent too many requests in a given amount of time (“rate limiting”).
- 431 Request Header Fields Too Large: The server is unwilling to process the request because its header fields are too large.
- 451 Unavailable For Legal Reasons: The user agent requested a resource that cannot legally be provided.
5xx Server Error Responses
This class of status code indicates that the server failed to fulfil an apparently valid request. servidor
- 500 Internal Server Error: The server has encountered an unknown error.
- 501 Not Implemented: The request method is not supported by the server and cannot be handled.
- 502 Bad Gateway: The server, while acting as a gateway or proxy, received an invalid response from the upstream server.
- 503 Service Unavailable: The server is not ready to handle the request. Common causes include a server being down for maintenance or being overloaded.
- 504 Gateway Timeout: The server is acting as a gateway and cannot get a response in time.
- 505 HTTP Version Not Supported: The HTTP version used in the request is not supported by the server.
- 506 Variant Also Negotiates: The server has an internal configuration error.
- 507 Insufficient Storage (WebDAV): The server is unable to store the representation needed to complete the request.
- 508 Loop Detected (WebDAV): The server detected an infinite loop while processing the request.
- 510 Not Extended: Further extensions to the request are required for the server to fulfil it.
- 511 Network Authentication Required: The client needs to authenticate to gain network access.
How Do HTTP Status Codes Affect SEO?
HTTP status codes directly influence your website’s Search Engine Optimisation (SEO) by communicating its health and accessibility to search engine crawlers like Googlebot. They affect your site’s ability to be crawled, indexed, and how users experience it.
Crawlability and Indexing
Search engines have a limited “crawl budget” for each site, meaning they only have so much time to spend crawling your pages.
- Good Codes (200s & 301s): When crawlers encounter a 200 OK status, they know the page is healthy and can be indexed. A 301 Moved Permanently redirect tells them to pass the old page’s ranking authority (link equity) to the new one, which is crucial for preserving your SEO value.
- Bad Codes (404s & 503s): Hitting too many 404 Not Found errors wastes your crawl budget, as Google spends time on dead ends instead of your important pages. A 503 Service Unavailable error tells crawlers the site is down; if this happens repeatedly, Google may crawl your site less frequently or even temporarily remove pages from its index.
User Experience and Ranking Signals
User experience is a significant, though indirect, ranking factor. Status codes play a big part in how a visitor perceives your site.
A user who frequently encounters a 404 Not Found page is likely to leave your website (a “bounce”). A high bounce rate signals to search engines that your site provides a poor user experience. Over time, this can lead to lower rankings, as search engines aim to show users the most reliable and helpful results. Similarly, if your site is often down (a 503 error), users will stop visiting, and so will search engines.
Best Practices for Managing HTTP Status Codes
This is where you provide actionable tips. It positions you as an expert and gives the reader a clear path forward. You could suggest practices such as:
- Regularly running site audits to catch broken links that lead to 404s.
- Creating a custom, helpful 404 page that guides lost visitors back to relevant content.
- Use 301 redirects for any content that has been permanently moved.
- Promptly contact your web host if you notice any 5xx server errors.
Conclusion About The List Of HTTP Status Codes
So, what are the HTTP status codes and their meaning? As we’ve seen, they are much more than just simple numbers; they are the essential language of the internet that reveals your website’s health.
Understanding them is a game-changer for spotting and fixing issues, ensuring a smooth experience for your visitors, and keeping search engines happy.
If you’re unsure where to begin checking your website’s health, let us help you out. Get in touch with Best SEO for a free SEO Audit today!
Talk to us, we’d be glad to help!
Frequently Asked Questions About The List Of HTTP Status Codes
How Do I Check The HTTP Status Code Of A Page?
You can use free online tools known as HTTP status code checkers. Simply enter the URL of the page you want to check, and the tool will show you the status code the server is returning. Many browser developer tools also have this function.
Is A 404 Error Bad For My Website’s SEO?
Having a few 404 errors is normal and won’t harm your site. However, a large number of them, especially for important pages, can negatively affect your user experience and SEO rankings. It’s best to fix them by redirecting the broken links to relevant, live pages.
What Is The Difference Between A 301 And A 302 Redirect?
A 301 redirect indicates that a page has moved permanently, and it passes most of the link authority (or “link juice”) to the new URL. A 302 redirect means the move is temporary, and it doesn’t pass on the same SEO value. For permanent moves, always use a 301.
Can I Customise My 404 Error Page?
Absolutely! Creating a custom 404 page is a great idea. You can make it helpful and on-brand by including a search bar, links to your homepage or popular pages, and a friendly message. It turns a frustrating experience into a more positive one.
