Understanding status codes is a must-know for any developer because they give an insight about what is exactly happening during any request. They let the developers understand if the request made is successful or not and if it is unsuccessful, where does the issue lie.

HTTP response status codes are predefined response codes sent by a server when a client makes a request.

These define what happened to the HTTP request made by the client.

HTTP response codes are three-digit numbers, with the first digit signifying one of the five predefined standard classes of response as shown in the following image:

Following are some common HTTP response status codes:

• 100 – Continue
• 200 – OK
• 201 – Created
• 301 – Moved Permanently
• 400 – Bad Request
• 404 – Not Found
• 415 – Media Type Not Supported
• 500 – Internal Server Error
• 502 – Bad Gateway

For More information refer to this link HTTP response status codes – HTTP | MDN (mozilla.org)