What you’ll need
A public URL and up to three crawler identities.
SEO TOOL · FREE TO USE
Pre-rendering Tester
See whether different crawlers receive different source HTML.
Free to use · No saved inputs01Rendering workspace
- 1 Add your input
- 2 Run the tool
- 3 Get your results
A public URL and up to three crawler identities. New here? Start with “Try an example”.
What this result can tell you
Compares source HTML for chosen user-agent strings, twice per setting. This does not verify real Googlebot access or prove pre-rendering or cloaking.
More settings (optional)
The URL and chosen crawler/language settings reach our inspection server, which contacts the target website. No login pages, credentials or private-network addresses are supported. Inputs and results are not stored.
Public target inspection · No paid API
How it works
Compare source HTML hashes, SEO metadata and readable text across user agents.
Know the limits
Differences suggest agent-dependent responses; they do not establish intent, cloaking or indexing.
GET FROM A QUESTION TO A NEXT STEP
Check whether crawler identities receive different HTML
Your website may serve a pre-rendered response to one user agent and an app shell to another. This pre-rendering tester compares source responses across selected crawler identities so you can see whether an agent-dependent delivery rule is working as intended. It is especially useful after a rendering-service change, CDN rule update or migration that affects how public pages are delivered.
How to use Pre-rendering Tester
Enter the public URL and select the crawler identities you want to compare. Keep the page and other settings consistent across the comparison.
Run the check and review response status, extracted text and SEO fields. The tool also compares repeated observations to help flag unstable content.
Investigate important content differences separately from small markup or hash changes. Export the evidence for your rendering or hosting team.
What do the results mean?
A different hash alone can result from dynamic markup. Changed text or metadata deserves closer review, but unstable baseline responses make the comparison inconclusive. This is source-response testing, not a complete measure of rendered parity, server-side rendering quality or search visibility.
What to do next
Use Fetch & Render when you also need to inspect the browser-rendered page, and test your production delivery rules after any change.
Keep the scope in mind
Differences suggest agent-dependent responses; they do not establish intent, cloaking or indexing.
Common questions about Pre-rendering Tester
Does different HTML prove cloaking?
No. Personalization, dynamic tokens and legitimate delivery architectures can create differences. The report cannot establish intent or a search-engine policy violation.
Is pre-rendering required for every JavaScript website?
The tool does not decide your architecture. It shows source-response differences. Choose a rendering approach based on the application, content needs and developer review rather than a single hash comparison.