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Hypertext Transfer Protocol

Hypertext Transfer Protocol (HTTP) is an application-layer protocol for transmitting hypermedia documents, such as HTML. It was designed for communication between web browsers and web servers, but it can also be used for other purposes. HTTP follows a classical client-server model, with a client opening a connection to make a request, then waiting until it receives a response. HTTP is a stateless protocol, meaning that the server does not keep any data (state) between two requests.

When accessing a web server or application, every HTTP request that is received by a server is responded to with an HTTP status code. Status codes come in the format of 3 digit numbers. The first digit marks the class of the status code:

  • 100–199 Informational responses
  • 200–299 Successful responses
  • 300–399 Redirects
  • 400–499 Client-side errors
  • and 500–599 Server errors - indicate problems on the server side

200 OK

The request has succeeded. All the requested data was located on the web server and transferred to the client. Internet users do not usually see this code. The meaning of the success depends on the HTTP method, but this code always announces a successful operation.

301 Moved Permanently

The 301 code means that the data requested from the client cannot be found under the given address since it has been moved permanently. Since the current location of the requested content is delivered in the status report, the browser can request the new address straightaway. The user is then forwarded to the new address and the old address is no longer valid. The 301 code also goes unnoticed because the URL in the address bar simply changes.

302 Moved Temporarily

Unlike the 301 code, which is a permanent redirection, the 302 informs the user that the requested data has temporarily been moved. With a 302 code the remaining information is specified so that an automatic redirection can take place. The old address remains valid.

403 Forbidden

The HTTP status code 403 tells the client that the requested data is access-protected and that the request cannot be performed due to the client not having authority. An automatically generated HTML page will let the user know about the access problem.

404 Not Found

The HTTP 404 Not Found client error response code indicates that the server can't find the requested resource. Links which lead to a 404 page are often called broken or dead links, and can be subject to link rot.

500 Internal Server Error

The 500 status code, or Internal Server Error, means that server cannot process the request for an unknown reason. Sometimes this code will appear when more specific 5xx errors are more appropriate. Internet users can presume that an administrator is working on the problem and that the server will be available later on.

Why Testomato checking /thisShouldNotExist page?

A 404 page is an page that appears when you click on a link that is broken and is therefore no longer (or in fact, never was) available.

Testomato is generate this check automatically for new Project and watch that your server response with correct 404 Not Found response code. Because some servers might response with 200 OK response codes even for non existing pages and that's harm SEO.

Content and links on 404 pages are so important because they give users a way out of the error page. Instead of closing the window or navigating away from your site, the user is able to find helpful and potentially relevant resources on another page.

Check out our 404 page