HTTP Status Codes explained with levels 200, 400, and 500

Introduction

When you visit a website or click on a link, your browser sends a request to the server that hosts the website. The server responds with a special three-digit number called an HTTP response code. This code tells you (and the browser) what happened with your request.

HTTP Status Code

1xx: Informational
  • 100 Continue: Covered as an example of informational responses.
  • 101 Switching Protocols: Highlighted to show protocol negotiation.
2xx: Success
  • 200 OK: The most common success code, indicating a request was successful.
  • 201 Created: Used for successful resource creation.
  • 204 No Content: Signifies successful processing with no additional response data.
3xx: Redirection
  • 301 Moved Permanently: Explains permanent URL redirection.
  • 302 Found: Discusses temporary redirection scenarios.
  • 304 Not Modified: Indicates no updates to the requested resource.
4xx: Client Errors
  • 400 Bad Request: Covers errors due to invalid client requests.
  • 401 Unauthorized: Explains the need for proper authentication.
  • 403 Forbidden: Highlights access denial scenarios.
  • 404 Not Found: Details the most recognized error for missing resources.
  • 429 Too Many Requests: Discusses rate-limiting issues.
5xx: Server Errors
  • 500 Internal Server Error: Describes generic server-side errors.
  • 502 Bad Gateway: Highlights upstream server communication issues.
  • 503 Service Unavailable: Explains server unavailability due to overload or maintenance.

Why HTTP Status Codes Matter for SEO

HTTP status codes are essential for SEO because they impact how search engines interact with your website. Here’s why they matter.

Helping Search Engines Crawl Your Sit

 2xx (Success): These codes tell search engines that your pages are working fine. A healthy website with no errors improves crawl efficiency.
3xx (Redirection): Permanent redirects (301) pass SEO value to the new URL, while temporary redirects (302) don’t. Misusing them can confuse search engines.

Avoiding Penalties for Errors

4xx (Client Errors): Pages with 404 errors (not found) or 403 errors (forbidden) frustrate users and may lead to lower rankings. Too many broken links can hurt your SEO.
5xx (Server Errors): Frequent 500 (server error) or 503 (service unavailable) codes tell search engines your site is unreliable, causing them to rank it lower.

Improving User Experience

Search engines prioritize user experience:

  • Working pages (2xx) = Happy users.
  • Error pages (4xx, 5xx) = Frustrated users and higher bounce rates.
Handling Redirects Properly

Redirects (3xx) ensure users and search engines land on the right pages. Mismanaging them can cause:

  • Broken links.
  • Loss of SEO value (link equity).

Common HTTP response codes

1xx: Informational

these mean: “The server got your request and is working on it.”

  • 100 Continue: The server is okay with your request so far, so keep going.
2xx: Success

These mean: “Everything worked!“

  • 200 OK: Everything worked, and you got what you asked for.
  • 201 Created: Something new was successfully made (like a new account).
  • 204 No Content: Your request worked, but there’s nothing to show (e.g., after deleting something).
3xx: Redirection

These mean: “The page or resource is somewhere else.“

  • 301 Moved Permanently: The page has a new permanent address.
  • 302 Found: The page temporarily moved but will come back.
  • 304 Not Modified: The page hasn’t changed, so no need to download it again.
4xx: Client Errors

These mean: “There’s something wrong with the request.“

  • 400 Bad Request: Your request had an error (e.g., wrong data).
  • 401 Unauthorized: You need to log in or provide access credentials.
  • 403 Forbidden: You don’t have permission to access this page.
  • 404 Not Found: The page you’re looking for doesn’t exist.
  • 429 Too Many Requests: You’ve made too many requests—try again later.
5xx: Server Errors

These mean: “Something went wrong on the server’s side.”

  • 500 Internal Server Error: Something went wrong on the server’s side.
  • 502 Bad Gateway: The server got a bad response from another server.
  • 503 Service Unavailable: The server is busy or down for maintenance.

Conclusion

HTTP response codes are like messages that tell you if a website request worked or not. They help users know what’s happening, help developers fix issues, and let search engines understand your site better.

HTTP response codes are the internet’s way of keeping communication clear. When you know how to handle them, your website becomes more reliable, user-friendly, and successful.