Know your HTTP status codes

HTTP (Hypertext Transfer Protocol) status codes - a mouthful we know - are a challenge to wrap your head around. So, we've taken it upon ourselves to provide you with the best guide to help you to become a HTTP status code expert!

The Internet is essentially made up of two things - clients and servers. A web client is anything from Chrome to Firefox. Every time you click on your browser (no matter what device you use) you are accessing the internet through that web client. Whenever you go to a website you make a request to a server, the server then responds. The same applies to any link you may click on a website too. But where do HTTP status codes fit into all of this?

Status codes tell us whether the request was a success, failure or something in-between. There are 5 main types of status codes you should be aware of:

1XX (100 block status codes) - Informational.

The server hasn't fully completed the request and is a sort of transitional phase. 100 block status codes are less commonly seen but are worth knowing about.

• HTTP Status Code 100 - Continue
• HTTP Status Code 101 - Switching Protocol
• HTTP Status Code 102 - Processing

2XX (200 block status codes) - Successful.

Below are the most common 200 block status codes you will come across. The most frequently seen being the 200 status code for OK. This group of codes informs you that your request was successful and nothing further needs to be done.

• HTTP Status Code 200 - OK
• HTTP Status Code 201 - Created
• HTTP Status Code 202 - Accepted

3XX (300 block status codes) - Redirection.

These inform you that there are further things required in order for the request to be finished. This can be because the desired page has been moved to a different URL.

• HTTP Status Code 300 - Multiple Choice
• HTTP Status Code 301 - Moved Permanently
• HTTP Status Code 304 - Not Modified
• HTTP Status Code 307 - Temporary Redirect

4XX (400 block status codes) - Client-side error.

These error codes appear when the error has been caused by the client. These are needed to be rectified by the client.

• HTTP Status Code 400 - Bad Request
• HTTP Status Code 401 - Unauthorized
• HTTP Status Code 403 - Forbidden
• HTTP Status Code 404 - Not Found
• HTTP Status Code 410 - Gone

5XX (500 block status codes) - Server-side error.

These codes tell you that the server has failed in completing the request. The server will be well aware of this error it has encountered.

• HTTP Status Code 500 - Internal Server Error
• HTTP Status Code 501 - Not Implemented
• HTTP Status Code 502 - Bad Gateway
• HTTP Status Code 503 - Service Unavailable

Hopefully this guide has helped you get to grips with the all-exciting HTTP status codes and be able to recognise and understand them should they appear when you conduct any kind of search.