When talking about HTTP status codes, we are referring to all those short notes from a server that can be inserted into a web page. These are messages from the server that help us check whether the request to view a particular page of our website. Although it seems somewhat science fiction, these messages are returned every time a browser interacts with a server.
Are you the owner and developer of a website? If you’re still here, this post interests you. Below we will show you everything you need to know to understand HTTP status codes.
It is an infallible tool for diagnosing a website’s configuration errors and is essential to understanding its correct operation. Are you prepared? We start.
What is an HTTP response code?
Imagine the following scenario. You are in front of your computer or mobile device and click on a specific link (or you type the URL by hand). Next, click on the Enter button. At that time, your browser will send a request to the web server of the site you are trying to access. That server will receive and process this request, returning all relevant resources and an HTTP header.
HTTP status codes are often colloquially categorized as “invisible” as they are delivered to the browser in the HTTP header without us noticing. However, we can see a warning in our browser when something goes wrong. It is their way of warning us that “something is not right or that one of the codes is not going to work.”
A good trick to know the status codes that a browser like Chrome or Firefox does not usually show is through various tools available on the net. One of the best examples is found in Web Sniffer.
Types of HTTP status codes that exist
HTTP status codes are usually grouped into five subgroups of interest. They include:
- 100s – These informative codes are the perfect indicator to know if the request initiated by the browser continues.
- 200s – In this case, the codes successfully returned once the browser request was received, understood, and processed by the server.
- 300s – It applies to all those redirect codes returned. They occur when a new resource has been substituted for the requested resource.
- 400s – Applicable when the requested code has had problems.
- 500s – In these scenarios, server error codes indicate that the request was accepted. However, there is a server error preventing it from being fulfilled.
Once we know these categories, we will delve into each type.
Informative answers
- Code 100 (Continue): It is a provisional response indicating that everything is correct. In this case, the client will have to continue with the request or ignore it if the request is finished.
- Code 101 (Changing protocols): The browser has asked the server to change protocols. Finally, the server will have complied.
- Code 103 (First notices): Allows some response headers to be returned before the rest of the server response is prepared.
Successful responses
- Code 200 (Everything is ok): This code allows us to indicate that the requested page has been loaded correctly. That is, it acts as expected.
- Code 201 (Created): The upload request has been completed successfully. Finally, the creation of a new resource will be possible.
- Code 202 (Accepted): Here the crafted request has been accepted for processing. However, it is still in the process of loading. Finally, ultimately, it will lead to a certain complete answer or not.
- Code 203 (Unauthorized Information): This code means the request has been completed successfully once a proxy has been used. This means that the content was not obtained from the requested source initially.
Redirects
- Code 300 (Multiple Choices): There may be several possible resources with which the server can effectively respond to your browser’s request. In this case, it means that a browser will have to choose between these various alternatives.
- Code 301 (The resource has been transferred permanently): This code implies that the redirection remains permanent from the domain. Upon entering a page with the 301 code, the user will immediately be redirected to another.
- Code 302 (The requested resource has been moved but found): It is usually used with temporary URL redirects.
- Code 307 (Temporary Redirect): Unlike 302, in this case, the HTTP method is not allowed to change.
Client errors
- Code 400 (Bad request): This error code indicates that the page you want to access cannot be found in this case. The main reason is that it will be due to a fault in the user’s typing. It is also often applicable when the requested page once existed but no longer exists.
- Code 401 (Unauthorized): This error code appears when a password is required to enter the site. Immediately, it will take the user to a screen to fill them in to continue with the process.
- Code 403 (Access to this resource is prohibited): This HTTP code indicates that the user’s request to enter a server is not allowed. You must be registered on a platform to access such exclusive content.
- Code 404 (Not found): In this case, the browser does not find the page you are looking for because it does not exist on the web page.
- Code 408 (The server timed out, waiting for the rest of the browser request): It is a prevalent mistake when many people are trying to request the same website simultaneously. In this case, the server timed out for the connection.
- Code 410 (The requested resource has left and will not return): HTTP code 410 means that the requested site no longer exists and is necessary for search engines to remove it from possible searches by users.
Server errors
- Code 500 (There was an error on the server): This code references internal web errors, making it impossible for the server to generate the HTML code to return to the user.
- Code 503 (The server is not available): This HTTP error code indicates that the server cannot respond to the request. The main reason is that it is congested or undergoing.
Maintenance
- Code 504 (Gateway Timeout): In this case, the 504 error means that the page has timed out. It usually happens when the page has a code that has not finished executing in its entirety.
- Code 509 (Bandwidth Limit Exceeded): It should be noted that this error is indicated once the bandwidth limit available on a specific website’s server has been exceeded.