What Is a 404 Checker?
A 404 checker is a tool that checks website URLs and identifies pages returning an HTTP 404 “Not Found” response. It helps website owners find missing pages, broken URLs, and unexpected errors so they can determine whether a page should be restored, redirected, or intentionally remain unavailable.
A 404 response can occur when a page is deleted, a URL changes, a permalink structure is modified, or someone requests an incorrect URL.
A 404 response is not automatically a problem for SEO. If a page was intentionally removed and there is no relevant replacement, returning a proper 404 can be appropriate.
How Does the 404 Checker Work?
The AISEOgic 404 Checker is a 404 checker tool designed for URL checking. It provides two ways to check URLs: you can scan URLs from a sitemap or paste specific URLs manually.
Scan URLs From Your Sitemap
Enter your domain or XML sitemap URL to check URLs available through your sitemap.
The tool can scan up to 300 pages from your sitemap, with up to 50 pages processed per click.
This can be useful when reviewing a website after a redesign, migration, URL restructuring, content cleanup, or other major changes.
Check Specific URLs
You can also paste specific URLs, one per line, instead of using a sitemap.
This option is useful when you already have a list of URLs that you want to investigate.
Review the Results
The purpose of checking URLs is not simply to find errors.
After identifying a 404 response, determine why the URL is unavailable and whether the page should be restored, redirected, or intentionally remain unavailable.
404 Checker Key Facts and Data
The AISEOgic 404 Checker can scan up to 300 pages from an XML sitemap and processes up to 50 sitemap URLs per click. Users can also submit specific URLs individually, with one URL entered per line.
The checker can identify common HTTP responses including 200 OK, 301 Redirect, 302 Redirect, 404 Not Found, 410 Gone, and 500 Server Error.
A 404 response means the requested resource was not found. A 301 response indicates a permanent redirect, while a 302 response indicates a temporary redirect. A 410 response indicates that a resource is permanently gone, and a 500 response indicates a server-side error.
These measurable checks can help website owners review important URLs after website migrations, redesigns, permalink changes, content updates, and technical SEO audits.
Finding and fixing 404 errors helps visitors reach the pages they need and keeps your website easier to navigate. To learn how to improve your content’s visibility in generative AI search experiences, read our guide to Generative Engine Optimization (GEO).
404 Checker Examples
See how the 404 Checker can be used in common website maintenance and technical SEO situations.
Example 1: Find broken pages from a sitemap
Example: Check a website sitemap for 404 errors
Suppose your website has recently been redesigned and some URLs may have changed.
Input:
https://yoursite.com/sitemap.xmlRun the scan to check URLs listed in the sitemap.
Example results:
URL Status Action /blog/seo-guide200 OK Keep /old-seo-guide404 Not Found Investigate /seo-tools301 Redirect Review redirect If
/old-seo-guidewas accidentally deleted, restore it. If the content permanently moved to a relevant new URL, consider a 301 redirect.
Example 2: Check specific URLs
Your tool supports pasting URLs one per line, so you can use it to check a list of important URLs.
Example: Check a list of important URLs
If you already have a list of URLs you want to test, paste them directly into the checker:
https://yoursite.com/abouthttps://yoursite.com/serviceshttps://yoursite.com/old-pagehttps://yoursite.com/contactThe checker can identify which URLs return 200, 301, 404, or other responses.
Example 3: Website migration
Website migrations can sometimes create broken URLs or missing pages.
Example: Find 404 errors after a website migration
Imagine you moved your website from an old URL structure:
/services/seoto:
/seo-servicesBefore and after the migration, check important URLs with the 404 Checker.
If the old URL returns 404 but the content has moved to
/seo-services, you can investigate whether a relevant 301 redirect should be added.This helps you identify unexpected missing pages after a migration.
Example 4: Deleted page
A 404 checker can also help you identify pages that may have been accidentally deleted.
Example: Find an accidentally deleted page
You notice that an important blog post is no longer loading:
https://yoursite.com/blog/technical-seo-guideRun the URL through the checker.
Result:
404 Not FoundIf the page was deleted accidentally, restore the page. If it was intentionally removed and there is no relevant replacement, keeping a proper 404 may be appropriate.
Example 5: Internal link problem
Broken internal links can lead visitors and search engines to pages that no longer exist.
Example: Find a broken internal URL
Suppose one of your pages contains a link to:
https://yoursite.com/services/seo-auditbut that URL no longer exists.
The 404 Checker identifies the URL as 404 Not Found.
You can then update the internal link to the correct URL or restore the missing page.
How to Find 404 Errors on a Website
Finding 404 errors is an important part of maintaining a website, especially when it contains many pages, products, articles, categories, or landing pages.
Use URL checking to find broken URLs and identify internal URL problems that may lead visitors or search engines to missing pages.
Start by reviewing URLs that are important to your website. Pay particular attention to pages that:
- Receive organic or referral traffic
- Have valuable backlinks
- Appear in your sitemap
- Are linked prominently from other pages
- Represent important products, services, or resources
A 404 found during an audit does not always require a redirect.
If the content genuinely no longer exists and there is no relevant replacement, a proper 404 may be the correct response.
For important pages that unexpectedly return 404, investigate the reason and determine whether the page should be restored or redirected to an appropriate replacement.
What Does a 404 Error Mean?
HTTP 404 means that the requested resource could not be found. You can learn more about the HTTP 404 Not Found status code in the MDN HTTP documentation.
Checking the URL status helps confirm whether a missing URL is actually returning HTTP 404 or another status code.
When a browser, user, or search engine requests a URL that does not exist, the server can return a 404 “Not Found” response.
A 404 error can occur for several reasons, including:
– A page was deleted
– A URL was changed
– A permalink structure was modified
– An internal link contains an incorrect URL
– A website migration changed URL structures
– A product, service, or resource was permanently removed
– Someone requested an incorrect or outdated URL
The appearance of a “Page Not Found” message is not enough by itself to determine the actual HTTP response.
Checking the status code can help confirm whether the server is returning the expected response.
For permanently removed content with no suitable replacement, a proper 404 or 410 response can be appropriate.
Why Do 404 Errors Matter for SEO?
A 404 error is not automatically bad for SEO. Websites naturally have some URLs that no longer exist, and intentionally removed pages can legitimately return a 404 response.
The main concern for 404 errors for SEO is an unexpected 404 on a URL that should still be available.
For example, an old product that has been permanently discontinued may legitimately return 404. However, an important service page accidentally deleted during a redesign should probably be restored or redirected to an appropriate replacement.
From a 404 SEO perspective, website owners should investigate important URLs that unexpectedly return errors and make sure the HTTP response accurately represents the page’s actual status.
Google explains that 404 errors can be normal for URLs that no longer exist, while important pages that have moved or should still exist may require further investigation. See Google’s guidance on 404 and soft 404 errors for more details.
404 checking can therefore be part of a broader technical SEO workflow that includes website migrations, internal link checks, sitemap reviews, URL changes, and regular website maintenance.
How to Fix 404 Errors
The correct solution depends on why the 404 exists.
If a page was deleted by mistake and the content is still needed, restoring the original page may be the best solution.
If the content has permanently moved to a clearly equivalent URL, a relevant 301 redirect can help users and search engines reach the new location. See Google’s documentation on redirects for guidance on permanent and temporary redirects.
A redirect should point to a genuinely relevant replacement rather than an unrelated page.
If content has been permanently removed and there is no suitable replacement, returning a proper 404 or 410 can be appropriate.
Not every missing URL needs to be redirected.
Finding broken URLs helps you identify pages that may frustrate visitors or interrupt important website journeys. Learn about AISEOgic’s broader approach to technical and AI SEO auditing in its platform announcement, and explore more website optimization tips on the AISEOgic YouTube channel.
How to Create a Helpful 404 Page
A custom 404 page should clearly tell visitors that the requested content could not be found while providing useful ways to continue browsing the website.
A helpful 404 page can include:
– A clear “Page Not Found” message
– A link to the homepage
– Links to important website sections
– Popular resources or content
– A site search option
– Helpful navigation back to relevant content
A custom 404 page should still return an actual HTTP 404 status when the requested page does not exist.
The goal is to make the error understandable and useful for visitors rather than simply displaying a generic error message.
When Should You Run a 404 Check?
There is no need to wait until visitors report broken pages.
Consider checking your website:
– After a website migration
– After changing permalink structures
– After deleting large amounts of content
– After redesigning navigation
– After changing domains
– After removing products or services
– During regular technical SEO audits
– When Search Console reports unexpected crawling problems
Regularly checking important URLs can help you identify unexpected missing pages and maintain a cleaner website structure.
Common HTTP Status Codes
HTTP status codes communicate the result of an HTTP request. The HTTP Semantics specification (RFC 9110) defines the standard meanings of response status codes, including 404 Not Found and 301 Moved Permanently.
Understanding common HTTP status codes makes it easier to interpret the results of a URL check.
200 OK
A 200 response generally indicates that the requested resource was successfully returned.
If a page appears to be a “Not Found” page but returns HTTP 200, it may represent a soft 404 situation and should be investigated.
301 Redirect
A 301 redirect indicates that a URL has been permanently redirected to another location.
When content has permanently moved to a relevant replacement URL, a 301 redirect can help users and search engines reach the new location.
302 Redirect
A 302 response indicates a temporary redirect. Whether it is appropriate depends on the reason for the redirect and how the website is configured.
404 Not Found
A 404 response indicates that the requested resource could not be found.
A 404 is not automatically an SEO problem. It can be the correct response when content has been intentionally removed and there is no suitable replacement.
410 Gone
A 410 response can be used when a resource has been permanently removed and is intentionally no longer available.
500 Server Error
A 500-level response indicates a server-side problem and should generally be investigated separately from a normal 404 response.
Frequently Asked Questions About 404 Errors
What Is a 404 Checker?
A 404 Checker identifies URLs that return an HTTP 404 “Not Found” response. It can help website owners find missing pages and investigate broken URLs during website maintenance or technical SEO audits.
Is a 404 Error Bad for SEO?
A 404 error is not automatically bad for SEO. Normal 404 responses are a natural part of the web, but unexpected 404s on important pages should be investigated and corrected when appropriate.
How Do I Find 404 Errors on My Website?
You can use a 404 Checker to inspect website URLs and identify pages returning 404 responses. For additional troubleshooting, website owners can also review crawling and indexing reports in Google Search Console.
What Is the Difference Between a 404 and a Broken Link?
A 404 is an HTTP status code indicating that a requested resource was not found. A broken link is a link that leads users to an unavailable or incorrect destination, which may result in a 404 or another response.
Should I Redirect Every 404 Page?
No. A redirect is appropriate when the content has moved to a relevant replacement URL. If the content has been permanently removed and there is no suitable replacement, returning a proper 404 or 410 can be the better choice.
How I Check 404 Errors?
To check 404 errors, enter your website domain or XML sitemap into a 404 checker, or paste specific URLs into the tool. The checker verifies the URL status and identifies URLs returning HTTP 404 “Not Found” responses.
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