Analyze Redirect Chains, Soft 404s and Broken Links with no404 Trace

When you open a URL, you usually see only the final page.

What happens before that final page can be much more complicated.

A request might first hit a 301 redirect, then a 302, then trigger a JavaScript redirect before finally reaching its destination.

The page may eventually load correctly, but the journey can still contain unnecessary hops, incorrect status codes, performance problems or even a soft 404.

no404 Trace is a free Chrome extension designed to show what your browser actually did when opening a URL.

Instead of stopping at HTTP redirects, it also detects client-side redirects such as meta refresh and JavaScript navigation and combines them into the same redirect chain.

See the complete redirect chain

Most redirect checking tools focus primarily on network-level responses.

no404 Trace looks at both the network layer and the page itself.

That means a single trace can include:

• HTTP redirects

• Meta refresh redirects

• JavaScript redirects

in one continuous chain.

For each hop, you can inspect information such as the HTTP status code, response time, remote IP address, cache state and response headers.

This becomes particularly useful during website migrations.

A URL reaching the correct destination does not necessarily mean the redirect configuration is healthy.

For example:

old URL → temporary redirect → another URL → JavaScript redirect → final page

may eventually send the visitor to the correct page, but the unnecessary hops are still worth investigating from both a performance and technical SEO perspective.

Is it a 301 or a 302?

One of the most common questions during a migration is whether redirects are using the intended HTTP status code.

A permanently moved URL may be expected to return a 301, while a misconfigured system could return a temporary 302 instead.

no404 Trace displays each step individually, making these situations easier to identify.

Other redirect responses such as 307 and 308 are also visible.

This is especially useful for:

• domain migrations,

• CMS migrations,

• URL structure changes,

• HTTP to HTTPS transitions,

• old product URL migrations,

• category restructuring.

Detect soft 404 pages

Not every broken page returns a real 404 status code.

Some pages respond with 200 OK while the actual content tells visitors that the requested page could not be found.

These are commonly known as soft 404s.

no404 Trace evaluates potential soft 404 pages using multiple weighted signals instead of relying on a single indicator.

Signals include factors such as:

• page title,

• H1,

• URL path,

• error-page markup,

• noindex directives,

• thin content,

• body copy,

• canonical URLs pointing to the homepage.

This helps surface URLs that technically return a successful response but may not represent a useful or valid destination.

Redirect chain health score

The number of redirect hops is only one part of redirect quality.

no404 Trace evaluates a chain against a set of technical rules and generates a health score out of 100.

Checks include issues such as:

• redirect loops,

• long redirect chains,

• temporary redirects where a permanent one may be expected,

• HTTPS downgrades,

• insecure final destinations,

• dropped query parameters,

• cross-domain handoffs,

• noindex pages,

• slow responses.

This makes it easier to understand not just how a redirect chain works, but where potential issues may exist.

Detect JavaScript and meta refresh redirects

Not every redirect happens through an HTTP response.

A page can redirect visitors using JavaScript methods such as:

location.assign

location.replace

or related browser navigation methods.

HTML pages can also use meta refresh redirects.

These client-side redirects may not appear in tools that only inspect HTTP responses.

no404 Trace detects them and stitches them into the main redirect chain.

The result is a closer representation of the route the browser actually followed.

Scan a page for broken links

A page itself may work correctly while some of the links inside it are broken.

The built-in link scanner checks links on the current page and identifies problematic destinations.

Links are scanned in parallel, using HEAD requests with a GET fallback where necessary.

Broken links can then be highlighted directly on the page.

This is particularly useful for:

• long-form content,

• documentation,

• landing pages,

• older articles,

• post-migration checks.

Re-check without browser cache

Browser caching can sometimes hide the current behavior of a URL.

no404 Trace can re-run a request while bypassing the browser cache.

This makes it easier to confirm whether a redirect has actually changed on the server or whether you are still seeing cached behavior.

Export your results

Technical audit results often need to be shared or documented.

no404 Trace supports one-click exports in:

• Markdown

• CSV

• JSON

The JSON export can also include full response header information.

This can be useful when documenting migrations, reporting redirect problems or sharing audit results with a development team.

Trace history

The extension keeps your latest 50 traces locally.

This allows you to revisit URLs you previously inspected without starting from scratch.

History is stored locally using Chrome storage.

Privacy

no404 Trace does not require an account.

Its core functionality runs inside the browser.

There is no analytics service, remote code or external server receiving your browsing data.

The only additional network requests are actions you explicitly initiate, such as cache-bypassing re-checks or link scans, and those requests go directly to the website being inspected.

Who is no404 Trace for?

The extension can be useful for:

• SEO audits

• domain migrations

• CMS migrations

• website redesigns

• URL restructuring

• broken-link checks

• soft 404 analysis

• redirect chain analysis

• technical SEO troubleshooting

Developers, SEO professionals, agencies and website owners can use it to inspect how a URL behaves inside a real browser.

no404 Trace vs No404

no404 Trace is primarily an inspection tool.

You open a URL and analyze its redirect chain, HTTP behavior, soft 404 signals and broken links.

No404 operates at a different stage.

It monitors real 404 requests reaching your website and helps route that traffic toward relevant live pages.

In simple terms:

no404 Trace → identify the problem.

No404 → detect and recover real 404 traffic.

For example, you can use no404 Trace before a migration to test whether redirect rules work as expected.

After the migration goes live, No404 can help you identify the URLs that real users, search engines and external backlinks are still requesting but that no longer exist.

This creates a useful two-stage workflow:

Before launch: inspect and validate redirects with no404 Trace.

After launch: monitor real 404 traffic and recover missed URLs with No404.

Why redirect analysis matters

Redirects are often treated as a simple technical detail.

In practice, they can affect crawl efficiency, page load time, user experience and how clearly a website communicates URL changes to search engines.

A redirect that eventually reaches the correct destination may still have problems.

For example, it may:

• pass through several unnecessary hops,

• use a temporary redirect instead of a permanent one,

• downgrade from HTTPS,

• drop important query parameters,

• end on a noindex page,

• rely on JavaScript when a server-side redirect would be clearer,

• or arrive at a page that looks like a soft 404.

That is why checking only the final URL is not always enough.

The full route matters.

A practical migration workflow

A simple workflow with no404 Trace can look like this:

1. Open an old URL before launch.

2. Check every redirect hop.

3. Confirm the intended status codes.

4. Look for unnecessary intermediate redirects.

5. Verify that HTTPS is preserved.

6. Make sure query parameters are not lost.

7. Check the final page for soft 404 signals.

8. Scan important pages for broken internal links.

9. Export results for documentation or development review.

10. Repeat the test without cache when needed.

After deployment, continue monitoring real 404 traffic with No404 to find URLs that were missed during planning.

This is especially useful for large migrations where it is unrealistic to predict every old URL, backlink or user bookmark in advance.

Final thoughts

Redirect analysis is not just about answering the question:

“Does this URL return a 301?”

A useful analysis should also answer:

Where did the request start?

How many redirects occurred?

Which type of redirect was used?

Did the request stay on HTTPS?

Were query parameters preserved?

Did JavaScript or meta refresh change the route?

Did the final URL return a genuinely useful page?

Are there broken links on the page?

Could the final destination actually be a soft 404?

no404 Trace brings these checks together inside the browser and makes the full URL journey easier to inspect.

For migrations, technical SEO audits, broken-link checks and redirect troubleshooting, it provides a practical way to see what the browser actually experienced from the first request to the final destination.