Regex Tester Online
Write a regular expression, paste your test string, and see all matches highlighted in real time. Capture groups, flags, and match details are displayed instantly — all in your browser.
Open Regex TesterWhat Does the Regex Tester Do?
Regular expressions are powerful but tricky to get right. This tool lets you experiment with patterns interactively, seeing matches update as you type. No more guessing whether your pattern works — test it live.
- Real-time match highlighting as you type the pattern
- View all capture groups (numbered and named)
- Toggle flags: global, case-insensitive, multiline, dotall, unicode
- See match count, index positions, and group details
- Uses JavaScript's native RegExp engine
Why ToolPilot?
Browser-Only
Your test data stays on your device. Regex evaluation runs locally in JavaScript.
Instant Results
Matches highlight in real time. No submit button, no server latency.
No Sign-Up
No account, no email, no login. Open the page and start testing.
50+ Tools
Regex testing is one of 50+ free developer tools on ToolPilot.
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Frequently Asked Questions
- Which regex flavor does this tool use?
- This tool uses JavaScript's built-in RegExp engine, which supports features like lookahead, lookbehind, named capture groups, and Unicode properties.
- Can I set regex flags like global or case-insensitive?
- Yes. You can toggle flags including global (g), case-insensitive (i), multiline (m), dotall (s), and unicode (u).
- Does the tester show capture groups?
- Yes. Each match is displayed with its full match text and all capture groups (numbered and named) listed separately.