GSC Regex Builder & Tester

Free, no signup. Catch PCRE syntax GSC cannot run, then test a safe RE2 pattern locally. Put the pattern on line one and one query per line after it.

Built by Patrick Stox

RE2 rejects lookarounds, backreferences, atomic groups, and possessive quantifiers. Separate data sets with a line containing ---. Files never leave your browser.

Local data

Saved targets, named lists, and recent check summaries remain only in this browser.

Runs entirely in your browser — nothing you paste is uploaded or stored. 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 Gsc Regex Tester? 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. 
  
 
  
 
 
  
 
 
      
 
How to use it
 
     
  1. Write the regular expression on the first line. Do not wrap it in slashes.
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  2. Paste one Search Console query on each following line.
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  3. Select Analyze. Review syntax issues first, then the true/false match beside every query.
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  4. Copy a clean pattern into a Search Console custom query filter. Recheck the filtered total before using it in reporting.
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Example output Example data
 
This static example uses ^(how|what)\b against three illustrative queries. It shows the exact result shape; it is not connected to a Search Console property.
 
 
Syntax issues0
 
how to audit redirectsMatch: true
 
what is crawl budgetMatch: true
 
technical seo toolsMatch: false
 
 
What you get
 
Issues lists every incompatible token the linter recognizes, its character index, why RE2 rejects it, and a safer rewrite direction. An empty array means no known lint issue was found; it is not a guarantee that a complex pattern expresses your intended audience.
 
Match is the browser test result for that query. When the pattern has any lint or compile issue, all test rows return false rather than pretending the broken pattern ran successfully.
 
How it works
 
The linter scans for unsupported RE2 constructs including lookarounds, numeric and named backreferences, atomic and conditional groups, possessive quantifiers, and \Z. It also asks the browser regex engine to catch unbalanced brackets and other compile errors. Only a lint-clean pattern is applied to the supplied queries, with case-insensitive matching.
 
Features
 
     
  • Specific explanations and rewrite directions for common PCRE-to-RE2 mistakes.
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  • Per-query match results for a realistic list, entirely in the browser.
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  • Support for ordinary RE2-compatible anchors, groups, alternatives, classes, and quantifiers.
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Limitations
 
     
  • This is a compatibility linter and local tester, not Google's production RE2 runtime.
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  • JavaScript and RE2 differ at some Unicode and escaping edges; validate the final filter in Search Console.
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  • The tool does not connect to GSC, estimate matched clicks, or generate exclusion filters automatically.
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Frequently asked questions
 
What regex syntax does Google Search Console support?
Search ConsoleA free Google service that reports how a site performs in Google Search and surfaces problems with how Google crawls, indexes, and serves it. It's first-party data straight from Google — but you don't need it to appear in results. uses RE2 syntax. It supports common groups, alternation, character classes, anchors, and quantifiers, but not lookarounds, backreferences, atomic groups, conditional groups, or possessive quantifiers.
Why does a regex work in another tester but fail in Search Console?
Many general-purpose testers use PCRE or JavaScript regex. Those engines accept features that RE2 deliberately excludes. This tool flags the known incompatible constructs before testing the pattern.
Are matches case-sensitive?
No. This tester applies the pattern case-insensitively, matching the behavior expected for Search Console query filtering.
Does this tool send my queries anywhere?
No. The pattern and query list are processed in your browser and are not uploaded.
Can I use negative lookahead to exclude branded queries?
No. RE2 does not support lookahead. Use a Search Console exclude filter separately, or write an inclusive pattern for the terms you want to keep.
 
 
Next stepWhich Pages Should I Work On? — look up the exact spec and expected values.

Explore more
ToolBrand/Non-Brand SplitterToolGoogle Search Console CSV AnalyzerToolSEO Opportunity FinderArticleGoogle Search Console (GSC)ArticleSEO Due Diligence for M&AArticleRedirect Error (GSC Status)
 
 
 
Feature requests for Gsc Regex Tester
 

Upvote what you want most. New ideas can be submitted from the floating Feedback menu;
      requests appear here once approved, and the most-wanted rise to the top.

   
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Common issues & how to fix them
  
     
  •  Warnings Regex misses an intended query Fix: Adjust the pattern to include the missed query while rerunning the full intended and excluded test set. 
  •  Warnings Regex matches an unintended query Fix: Add a boundary, exclusion, or more specific token so the unintended query no longer matches. 
  •  Warnings Regex is broader than intended Fix: Replace broad wildcards with explicit terms and boundaries that describe only the intended query set. 
  •  Warnings Regex anchors exclude valid queries Fix: Remove or reposition ^ and $ anchors so they match the intended whole-query or substring behavior. 
  •  Information Case handling changes the match set Fix: Normalize case or enable case-insensitive matching when capitalization should not change membership. 
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