GSC Regex Builder & Tester

How to use it

1. Write the regular expression on the first line. Do not wrap it in slashes.
2. Paste one Search Console query on each following line.
3. Select Analyze. Review syntax issues first, then the true/false match beside every query.
4. Copy a clean pattern into a Search Console custom query filter. Recheck the filtered total before using it in reporting.

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.

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.
• Per-query match results for a realistic list, entirely in the browser.
• Support for ordinary RE2-compatible anchors, groups, alternatives, classes, and quantifiers.

Limitations

• This is a compatibility linter and local tester, not Google's production RE2 runtime.
• JavaScript and RE2 differ at some Unicode and escaping edges; validate the final filter in Search Console.
• The tool does not connect to GSC, estimate matched clicks, or generate exclusion filters automatically.

Frequently asked questions