What Are HTTP Status Codes?

HTTP status codes are three-digit numbers sent from a web server to your browser. They tell your browser whether the request for a webpage was successful, if something went wrong, or if additional action is needed.

These codes are divided into five categories, each starting with a different number, and each serves a unique purpose.

The Five Categories of HTTP Status Codes

1xx: Informational Codes

• 100
• 101

This category is like a quick “heads-up” from the server, letting your browser know the request has been received and is still being processed.

While these codes are rare for everyday users, they’re helpful for developers during testing or debugging. Examples include 100 Continue and 101 Switching Protocols.

2xx: Success Codes

• 200
• 201

Success! If you see a 2xx code, the server handled your request perfectly. The most common is 200 OK, meaning the webpage loaded without any issues.

There’s also 201 Created, often used for APIs to indicate a resource was successfully created, like when you upload a file.

3xx: Redirection Codes

• 301
• 302

Redirection codes guide your browser to a new location. 301 Moved Permanently tells your browser that the resource has a new permanent URL, so it updates its bookmark. 302 Found temporarily redirects you, often used for maintenance or short-term changes.

4xx: Client Errors

• 404

If you encounter a 4xx code, the problem is on your end—or at least with the request you sent. The infamous 404 Not Found means the webpage you’re looking for doesn’t exist, often due to a typo or a broken link.

Another common code is 403 Forbidden, which tells you the page exists, but you don’t have permission to access it.

5xx: Server Errors

• 500
• 503

When the server runs into trouble, it sends a 5xx code. The 500 Internal Server Error is a general-purpose error for when something went wrong on the server.

Another is 503 Service Unavailable, which usually means the server is overloaded or undergoing maintenance.

Why Do HTTP Status Codes Matter?

HTTP status codes aren’t just for developers—they can be useful for anyone.

For example, knowing a 404 error means the page doesn’t exist can save you from endless refreshing.

Website owners can use these codes to identify and fix issues, ensuring smooth user experiences.

They’re also essential for SEO. Search engines like Google pay attention to these codes when crawling your site.

Persistent errors like 404 or 500 can hurt your rankings, so addressing them promptly is important.

Commonly Encountered HTTP Status Codes

• 200 OK: Everything is working perfectly.
• 301 Moved Permanently: The page has a new home—update your bookmarks!
• 302 Found: Temporary redirect; the original link still works.
• 404 Not Found: The page doesn’t exist or the link is broken.
• 500 Internal Server Error: Something’s wrong on the server’s end.

How Can You Use This Knowledge?

Understanding HTTP status codes can help you troubleshoot issues while browsing or managing a website. If you’re building a website, monitoring these codes can improve user experience and ensure search engines index your site properly. And next time you see a 404, you’ll know exactly what it means!