HTTP Status Code
Hypertext Transfer Protocol Status Code
A three-digit number a server sends to a browser to report the result of a webpage request.
In Simple Terms
An HTTP status code is a three-digit number that shows the result of a request between your web browser and a server. While browsing the web, you might see "404 Not Found" appear when a page can't be found. That's the server using this code to tell your browser, "the page you're looking for isn't here." Even when a page loads without any problem, a success code - "200" - is quietly sent behind the scenes.
Behind the Name
The name says exactly what it is: a "code" - a short number - that reports the "status", or condition, of a request between your browser and a server.
Take a Closer Look!
An HTTP status code is the reply a server sends back to your browser to report the result of loading a website.
When you open a webpage on your computer or phone, your browser asks the server to "show me this page", and the server answers with a three-digit number that reports what happened.
Roughly speaking, the first digit of that three-digit number sets its general meaning.
For example, codes in the 200 range (starting with "2") mean the request succeeded, while codes in the 400 range (starting with "4") mean something went wrong on the browser's side, such as requesting the wrong URL. Codes in the 500 range (starting with "5") mean there's a problem with the server's own system.
Put simply, this code is what lets the browser instantly decide what screen to show next.
It also plays an important role in telling apart whether an error was caused by your own mistake or by a system problem on the website's side.