Regex

Regex Capture Group Tester

Inspect JavaScript regex capture definitions, non-capturing groups and lookarounds alongside per-match capture values.

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Group definitions

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Uses your browser’s JavaScript RegExp engine. Positions and lengths are zero-based UTF-16 code units; end positions are exclusive. Without g, matching returns only the first match. Sticky y starts at position 0.

Limits: 16,384 pattern code units, 200,000 text code units, 2,000 matches or split parts, and 4,000,000 output code units. User regex execution requires a local worker with a 1,500 ms timeout. Oversized results fail rather than being truncated.

Processed locally in your browser. Inputs and results are not uploaded or saved by this page.

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What does this tool do?

Inspect JavaScript regex capture definitions, non-capturing groups and lookarounds alongside per-match capture values. Code Station Regex tools use the JavaScript regular expression engine. Inputs: Regex Pattern, Test text, Flags. Outputs: Group definitions, Match captures.

How to use it?

Enter a pattern with groups or lookarounds and test text. Definitions and captured values appear separately. Choose “Test capture groups”, then copy individual result values if needed. Clear removes all inputs and results and restores option defaults.