Tue Jul 04 2023
Understanding the Meanings Behind Common HTTP Response Codes
Sometimes you may see that your computer screen shows the HTTP error codes and addresses - "The requested URL /does_not_exist was not found on this server". Sometimes you get this type of error code, sometimes didn't. So, what is HTTP response status codes and what do mean these codes? Here, in this article, we will explain HTTP response status codes and their meaning.
What is HTTP status code?
HTTP stands for Hypertext Transfer Protocol. It's a method to communicate between you and servers. When you click a link and types in a URL or submit a form, their browser sends a request to a server for information. It might be asking for a page, or sending data, that is called an HTTP Request. When a server receives that request, it sends back an HTTP Response, with information. One of the most common Response codes is 404. There are few more status codes sent by servers. These status codes indicate a provisional response.
The codes are grouped in five classes - informational responses, successful responses, redirects, client errors, and servers errors.
1. Informational responses
100 - Continue
100 indicates it's a part of a request that has been received without any problems and that the rest of the request should now be sent.
101 - Switching Protocols
101 means that the requester has asked the server to switch protocols; and the server has agreed to do.
102 - Processing
102 indicates that the server has received and processing that request, but not getting any response yet. It prevents the client through time out and assumed that lost the request.
103 - Early Hints
103 indicates that it used to return some response headers before final HTTP message.
2. Successful responses
200 means that the request was received and understood and it is being processed.
201 - Created
201 code indicates that a request was successful. As a result, a resource has been created.
202 - Accepted
202 indicates that server has received and it has been accepted for processing. It may not be processed immediately.
203 - Non-Authoritative Information
203 means that the request was received and information sent back from a third party.
204 - No Content
204 code means that the request was received, but there is no need to send any data back.
205 - Reset Content
205 code is a type of request from the server to reset the document.
206 - Partial Content
206 is a response to a request for part of a document. It used by advanced caching tools when a user agent requests only a small part of the page.
207 - Multi-Status
It indicates the information about multiple resources in situations where multiple status codes might be appropriate.
208 - Multi-Status
It responses the element to avoid enumerating the internal members of multiple bindings to the same collection repeatedly.
226 - IM Used
This the response is a representation of the result of one or more instance-manipulations applied to the current instance.
3. Redirection messages
300 - Multiple Choices
300 indicates that a resource has moved. It will also include a list of locations from which the user agent can able to select the most appropriate.
301 - Moved Permanently
301 indicates that the resource has permanently moved to a new location. The response should also include this location. The client to use the new URL
302 - Found
302 indicates that the resource has temporarily moved to a new location. The response should also include this location. The client should carry on using the same URL to access this resource.
303 - See Other
303 code indicates that the response to the request can be found at the specified URL and retrieve. It specify the address to which the response to the request can be found.
304 - Not Modified
304 is sent in response to a request that asked for the document only if it was newer than the one.
305 - Use Proxy
305 code tells the client that the requested resource has to be reached through a proxy.
306 - Switch Proxy
It originally means subsequent requests should use the specified proxy. But no longer it used.
307 - Temporary Redirect
307 code is sent when a document is temporarily available at a different URL.
308 - Permanent Redirect
It means the request and all future requests should be repeated using another URI. 307 and 308 parallel the behaviors of 302 and 301 but do not allow the HTTP method to change.
4. Client error responses
400 - Bad Request
400 indicates that the server did not understand the request because of bad syntax.
401 - Unauthorized
401 code indicates that the client must be authorized by the server before a resource can be accessed.
402 - Payment Required
402 code indicates as "reserved for future use". But it is not currently in use.
403 - Forbidden
403 indicates that the client cannot access the requested resource. It means the wrong username and password were sent in the request or the permissions on the server do not allow for that.
404 - Not Found
404 indicates that the requested resource was not found at the URL given.
405 code is returned when the client has tried to use a request method that the server does not allow.
406 - Not Acceptable
406 means that the response is of a form that the client cannot understand. A client sends, as part of a request, headers indicating what types of data it can use. 406 error is returned when the response is of a type.
407 - Proxy Authentication Required
407 code means that the client must be authorized by the proxy before the request can proceed.
408 - Request Timeout
408 means that the client did not produce a request quickly enough.
409 - Conflict
409 indicates that the server was unable to complete the request because a file would need to be edited, created or deleted.
410 code indicates that a resource has permanently gone.
411 - Length Required
411 code occurs when a server refuses to process a request because a content length was not specified.
412 - Precondition Failed
412 indicates that one of the conditions the request was made under has failed.
413 - Request Too Large
413 indicates that the request was larger than the server is able to handle, either due to physical constraints or to settings.
414 - URI Too Long
414 code indicates the URL requested by the client was longer than it can process.
415 code indicates that part of the request was in an unsupported format.
416 - Not Satisfiable
416 indicates that the server was unable to fulfill the request.
417 - Expectation Failed
417 means that the server was unable to properly complete the request.
The server refuses the attempt to brew coffee with a teapot.
This indicates the request was directed at a server that is not able to produce a response.
422 - Unprocessable Entity
This indicates the request was well-formed but was unable to be followed due to semantic errors.
This indicates the resource is being accessed is locked.
This indicates the request failed because it depended on another request and that request failed.
426 - Upgrade
This indicates the client should switch to a different protocol such as TLS/1.0, and given in the Upgrade header field.
428 - Precondition
This indicates the origin server requires the request to be conditional.
429 - Many Requests
This indicates the user has sent too many requests in given amount of time.
431 - Request Header Fields Too Large
This indicates the server is unwilling to process the request because either an individual header field or all the header fields collectively are too large.
451 - Unavailable
This indicates 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.
5. Server error responses
500 - Internal Server Error
500 code indicates that the server encountered something it didn't expect and was unable to complete the request.
501 - Not Implemented
501 code indicates that the server does not support all that is needed for the request to be completed.
502 - Bad Gateway
502 indicates that a server while acting as a proxy, received a response from a server further upstream that it judged invalid.
503 - Service Unavailable
503 code is most often seen on extremely busy servers. It indicates that the server was unable to complete the request due to a server overload.
504 - Gateway Timeout
504 code is returned when a server acting as a proxy has waited too long for a response from a server further upstream.
505 - HTTP Not Supported
505 code is returned when the HTTP version indicated in the request is not supported.
This indicates the server has an internal configuration error. Transparent content negotiation for the request results in a circular reference.
507 - Insufficient Storage
This indicates the chosen variant resource is configured to engage in transparent content negotiation itself and is therefore not a proper end point in the negotiation process.
508 - Loop Detected
This indicates the server detected an infinite loop while processing the request.
510 - Not Extended
This indicates further extensions to the request are required for the server to fulfill it.
511 - Network Authentication
511 code indicates that the client needs to authenticate to gain network access.