Whenever a user types a web page URL into their browser and presses Enter, the browser sends a request to a web server. The server responds with the requested page (plus any additional resources like images or scripts) and returns an HTTP status code with each request.
Most of the time, these HTTP status codes are not shown because the request was successful. However, when a server cannot access the requested resource, it provides an explanation through a specific response status code.
This article defines the most common HTTP status codes you might encounter and explains which ones could impact your SEO performance.
🔎 What Are HTTP Status Codes?
🔎 What Are HTTP Status Codes?
The HTTP status code is a three-digit number that tells the browser what happened when it tried to connect to the server. These codes communicate whether or not a request was successful.
They matter for SEO because successful requests create a better experience for users and search engine crawlers. Conversely, codes that indicate errors or missing resources can signal to Google that a website isn’t well maintained.
📊 Types of Status Codes
📊 Types of Status Codes
There are five main series of HTTP status codes. The first digit identifies the type of response:
1️⃣ 1xx — Provides Information
2️⃣ 2xx — Indicates Success
3️⃣ 3xx — Redirected page (moved to another URL)
4️⃣ 4xx — Client error (problem with the requested page)
5️⃣ 5xx — Server error (problem with the server’s connection)
🚀 Most Common HTTP Status Codes
🚀 Most Common HTTP Status Codes
There are more than 60 possible status codes, but these are the most frequent and most important for SEO.
✅ 200: Success
✅ 200: Success
This code means the request was successful and the server created a new resource. 2xx codes indicate everything is working correctly.
If a 200 code is not found, the Site Auditor will flag it with:
Status code not 200
🔁 301: Permanent Redirect
🔁 301: Permanent Redirect
A 301 redirect communicates that a page has been permanently moved to a new URL. When implemented correctly, it helps preserve link equity and improve SEO.
Common 301-related issues flagged by the Site Auditor include:
301 Does Not Redirect to HTTPS — Should redirect to HTTPS for user security.
Redirect URL not lowercase — Prevents duplicate content issues.
Internal links with 301 redirects — Google prefers updating internal links to the new URLs directly.
⚠️ 404: Not Found
⚠️ 404: Not Found
Status codes in the 400 range indicate a client error. A 404 occurs when the requested page doesn’t exist.
These errors hurt user experience and SEO since Google perceives dead links as poor maintenance.
Common 404 issues flagged:
Common 404 issues flagged:
URL gives soft 404
💡 What Causes a 404 Response Code?
Deleted/Moved Page — Add a 301 redirect to the new page.
Incorrect URL — Double-check link accuracy.
Caching Problems — Clear cached error pages.
Missing Asset — Replace or update missing files (images, CSS, JS).
🛠️ 500: Internal Server Error
🛠️ 500: Internal Server Error
500-level errors indicate the server encountered a problem processing a request.
If you see a 500 code, try these fixes:
Refresh your browser — A new request may succeed.
Delete browser cookies — May fix loading issues.
Deactivate plugins — Especially after new installations.
Try again later — The issue may be temporary.
🧩 How to Check HTTP Status Codes
🧩 How to Check HTTP Status Codes
It’s important to identify pages producing invalid responses since they can prevent users from accessing your content.
Option 1: Use Google Search Console
Option 1: Use Google Search Console
Navigate to Index > Pages.
Review displayed indexing errors (e.g., 404 or 500).
Click on an error to view affected pages.
Option 2: Use the Site Auditor Dashboard
Option 2: Use the Site Auditor Dashboard
After running your audit, go to the Issues tab.
Click Page URL.
Look for messages mentioning HTTP status codes.
Click See Affected Pages to view non-200 URLs.
Share this list with your web developer or an SEO expert for resolution.
🧭 Closing Note
Now that you understand the most important HTTP status codes for SEO, you can resolve web page errors that harm visibility. If you’re unsure why your URLs return specific codes, consider consulting a technical SEO agency for expert help.