Pre-publish Comparison

Free, no signup. Compare a draft HTML export with the current live HTML you supply before approving a release.

Built by Patrick Stox

Supply both HTML documents

1 MiB maximum per document. Oversized input is rejected in full; it is never silently shortened. Use HTML only—do not paste credentials, access tokens, personal data, or confidential source comments.

Runs entirely in your browser — nothing you paste is uploaded or stored. The tool does not fetch URLs, call AI, use credentials, persist input, or include source HTML in exports. Anonymous run-level outcome counters may be used for aggregate research; URLs, domains, IPs, and identifiers are never included, and no statistic is released below 100 runs.

Feedback
Report a bug

Found something broken in Prepublish Comparison? Let us know what happened — this goes straight to a private triage queue, not a public list.

What will be sent 
 No tool inputs, uploads, pasted source, complete results, query parameters, or URL fragments are attached automatically. You can edit or remove the selected passage above. Browser and anti-abuse metadata is processed for spam prevention. 
  
 
  
 
 
  
 
 
   
 
 
 
Sample report
 
Fabricated draft and live HTML
 
Regression: the draft removes one live hreflang declaration.
Changed: the title and heading outline differ.
Not evaluated: AI-crawler posture is not observable from the supplied HTML.
 
 
 
How to use it
 
  1. Export or view the complete HTML for the draft and current live page.
  2. Paste both documents or choose two local .html files. Inputs over 1 MiB are rejected.
  3. Choose which conservative regressions should block your release. Optionally fail when a selected signal could not be evaluated.
  4. Compare the normalized signal rows. Investigate blockers first, then confirm whether each changed row is intentional.
  5. Download CSV evidence or the machine-readable JSON gate report. The exports omit the supplied source HTML.
 
 
 
 
Release-gate policy
 
Choose which observed regressions should fail this check. This policy is yours—it is not a prediction that a release is safe or unsafe.
 
 
        
  
 
     
 Local data 
Saved targets, named lists, and recent check summaries remain only in this browser.
 
   
 
      
 
How it works
 
The parser scopes title, description, canonical, robots, hreflang, and JSON-LD evidence to the document head. Commented tags, script strings, and body-level decoys are ignored. HTML entities are decoded, JSON-LD object keys are normalized structurally, and heading levels plus text are compared as an ordered outline. The selected release policy is then applied by the shared deterministic seo-core gate evaluator.
 
Limits
 
The result covers only the two supplied documents. It does not fetch a live URL, render JavaScript, inspect HTTP headers, read robots.txt, verify hreflang reciprocity, validate schema eligibility, or determine whether a release should proceed. Malformed or unavailable evidence remains not evaluated.
 
Frequently asked questions
 
Does this fetch either page?
No. Supply each HTML document by pasting it or choosing a local .html file. Both documents and the comparison stay in this browser; neither page nor its contents are fetched or uploaded. A bounded anonymous usage ping may be sent after a run, but it contains no supplied HTML, URL, domain, IP, or identifier.
What happens when a signal cannot be evaluated?
The row stays not evaluated. A missing or malformed head, malformed JSON-LD, and crawler posture that HTML cannot establish are not treated as matches.
What counts as a regression?
The conservative regression label is reserved for removed observed evidence, removed hreflang declarations, a shorter heading outline or lost H1, and newly restrictive robots or crawler directives. Other differences are labeled changed for human review.
Why is AI-crawler posture not evaluated?
A pasted HTML document does not prove the site robots.txt policy or edge behavior for AI crawlers. The row is retained to make that evidence boundary explicit.
What does an export contain?
CSV contains the normalized comparison rows. The machine-readable JSON report adds the selected release policy, pass/fail result, and blockers. Neither export includes either pasted HTML document.
 
 
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Feature requests for Prepublish Comparison
 

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      requests appear here once approved, and the most-wanted rise to the top.

   
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