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HTTP Status Codes: A Complete Guide to the Most Common Error Codes

Aanchal Rathore
I am passionate blogger & developer.
・7 min read

Every time we want to visit a website, whether it is an online store to buy the latest mobile phone or check the movement of our bank account, you should enter the URL in the browser, or do a Google search. Once you click on the appropriate page, a request is made to the server to return the appropriate content and always returns the HTTP three-digit code.

Thanks to this HTTP status code, we can know whether our request has been completed correctly, or if there is an error that prevents the server from the back of content users or visitors trying to access.

If you have a web page is very important that you know and understand all of the different HTTP status codes that exist. These messages returned by the server is the best tool you can have to diagnose and solve certain problems or errors that may arise on your website.

For the avoidance of doubt, we will look forward to what is HTTP code, type of HTTP status codes that exist and most importantly HTTP code.

What is the HTTP status code?

HTTP status code is a message returned by the server each time the browser requests the server. If the server can restore the content requested by the browser, and no mistake, this HTTP code is not visible to users. Conversely, if something goes wrong, you will notice that the server returns an HTTP status code that indicates that something is not working as expected.

Depending on the status code returned by the server, we can get an idea of ​​the type of error that has occurred. That is why we say that when you have a web page is very important that you know the types of HTTP code so you can see what a mistake it was and quickly fix it.

Samples of HTTP codes

If the HTTP status code that is new to you, you will find that you are more used to seeing them when you try to access a web page than you think.

Do a 404 ring a bell? a very common mistake is still an HTTP status code that tells the user that the content they are trying to access is either not on the server or not available.

Response Types of HTTP Status Codes

HTTP status codes are standardized and listed in the Internet Assigned Numbers Authority (IANA) HTTP status code registry.

HTTP code is divided into five different categories and the first digit of the code allows you to identify what kind of response we are dealing with: informative responses, a successful response, redirects, error browser, and server errors.

1xx Status Code: This is an informative response and indicates that the browser can continue to make your request.
2xx status code: Association of 2xx code represents a satisfactory response, they merely indicate that the request is processed correctly, so ideally, all websites have returned HTTP code. Generally, as the request was successful, the status code is not displayed, the browser simply returns the user requested content.
3xx status code: HTTP Code refers to when the browser should perform additional actions, such as redirect.
4xx Codes Status: The status code beginning with a 4 refers to the errors generated by the web browser. In this case, users typically receive an HTML page in which they were told about the error.
5xx status code: HTTP Code also indicates an error, but on the webserver.

List of the Most Important HTTP codes

In each group the HTTP status code that we have seen before, various codes can be returned by the server.

1xx Status Codes

Code 100 - Continue: This status did the notification code that the server has received the first request and waits to receive further instructions from the browser.
Code 101 - Switching Protocols: It is used when the server receives the changes proposed by the browser. For example, changes from HTTP 1.0 to HTTP 1.1.
Code 102 - Processing: The server has received the request but has not completed it. This is to prevent the browser from interpreting that the request has been lost, but not yet completed.
Code 103 - Checkpoint: It is used to proceed with the request that was previously missing or cancelled.

2xx Status Codes

Code 200 - OK: Used when the request was completed. As this code shows that "everything is fine" is not usually shown to the end-user.
Code 201 - Created: browser inquiry has been completed successfully and the new resource has been created.
Code 203 - Non-Authoritative Information: Query Browser is completed successfully, but corresponds to a different server to the content of the request is made.
Code 204 - Not Contents: browser inquiry has been completed successfully, but the response does not display any content.
Code 205 - the Content: It is used when a user request is complete, but need to reload the page. It is very common when data is sent through the contact form and the page is reloaded.
Code 206 - Partial Content: It is used when the request is complete, but only part of the requested content is returned.
Code 207 - Multi-Status: An XML file that contains several different responses are returned, depending on the requests made earlier.

3xx Status Codes

Code 300 - Multiple Choices: Upon request, there is more than one option to access the same resources.
Code 301 - Moved Permanently: The requested resource has been permanently moved and the browser automatically redirected to the new location. 301 is a good choice for Google to punish us if we have too many 404 errors on our website.
Code 302 - Moved temporarily: The requested resource has been moved temporarily and the browser automatically redirected to the new location.
Code 303 - Other View: This code indicates that the requested resource has been moved, but do not redirect.
Code 304 - Not Modified: If a browser asks the server if the requested resource has been moved since the last visit, and it has not changed.
Code 305 - Use Proxy: HTTP code is used when the requested resource must be obtained through a proxy location which is located in the header.
Code 306 - Switch Proxy: This code is no longer used today, but it is reserved for cases in the future.
Code 307 - Temporary Redirect: The resource requested by the browser can be obtained elsewhere, but only for this request. For the future demand for the original location can be used.
Code 308 - Permanent Redirect: The resource requested by the browser in another location and change it permanently. Unlike the HTTP code 301, a new HTTP method for the request has not changed.

4xx Status Codes:

Code 400 - Bad Request: The server did not understand the request because the syntax is not the correct browser.
Code 401 - Unauthorized: The request made by the browser requires authentication.
Code 402 - Payment Required: This is the HTTP code reserved for future use.
Code 403 - Forbidden: The request made by the browser is correct, but access to the requested resource has been denied.
Code 404 not Found: The resources requested by the browser can not be found or is not available on the server. It is not possible to detect if the absence is temporary or permanent.
Code 405 - Method Not Allowed: Browsers use the method to obtain resources that are not accepted by the server.
Code 406 - Not Acceptable: The requested resource has a format that is not accepted by the browser.
Code 407 - Proxy Authentification Required: A status code is similar to 401, but in this case, the first browser must authenticate with a proxy.
Code 408 - Request Timeout: HTTP code is returned when the browser has taken so long to request that the server is no longer waiting for the request.
Code 409 - Conflict: The request could not be completed because there was a conflict with the requested resource.
Code 410 - Go: The requested resource could not be found and are not considered permanent presence. If there is a possibility that this is a temporary absence, HTTP code 404 should be used.
Code 411 - Length Required: The server returns an HTTP code when a request does not include the appropriate "Content-Length" header.
Code 414 - Request-URI Too Long: The URL that corresponds to the request was made too long to be processed. This occurs when an address has a lot of parameters.
Code 423 - Locked: HTTP code is displayed when the requested resource is blocked.
Code 429 - Too Many Requests: Browser makes so much demand within a certain period.

5xx Status Codes

Code 500 - Internal Server Error: The request made by the browser can not be completed as an unexpected error has occurred in the browser.
Code 501 - Not implemented: The server does not support the functionality required to respond to requests made by the browser.
Code 502 Bad Gateway: The server can not respond to browser requests because it acts like a proxy server or gateway, or have a reverse proxy is installed and has received an invalid response from the server said.
Code 503 - Service Unavailable: The server can not respond to a browser request for saturated or maintenance tasks are being done on it.
Code 504 - Gateway Timeout: The server can not respond to browser requests because it acts like a proxy server or gateway, or have a reverse proxy server installed and response time says it has timed out.
Code 505 - HTTP Version Not Supported: The server does not support the HTTP protocol version used in the browser request.
Code 509 - Bandwidth Limit Exceeded: It is widely used in the HTTP code cPanel and displayed when the bandwidth limit has been reached and the request could not be processed.
Code 510 - Not Renewed: This code is displayed when necessary to add an extension to the server so that it can process the request.
Code 511 - Network Authentification Required: Browser must authenticate itself to make a request.

Summing Up

Knowing and understanding the different HTTP code that the server can back it is important to detect and troubleshoot possible errors on your website. Furthermore, this status code plays a fundamental role in the position of your website SEO.

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