Does this regex tester support capture groups?
Yes. Captured groups are listed under each match when present.
Free Regex Tester Online
Test regex patterns quickly against sample text in your browser.
Regex Tester
Test regex patterns against input strings.
🔒 Processes data locally in your browser — input isn’t uploaded or stored.
Why Use This Tool
This regex tester is useful for validating pattern logic, checking flags, and reviewing matched output before using expressions in production code or scripts. Common next steps include Text to ASCII Converter and Base64 Encode / Decode.
What This Tool Does
Enter a regex and sample text, run the test, and review matches.
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How to Use
- Enter pattern, flags, and test string.
- Optionally set replacement text to preview replace output.
- Review match indexes, capture groups, and replacement preview.
Common Mistakes
- Forgetting the global flag when expecting multiple matches.
- Testing with unrealistic sample text that misses edge cases.
- Using greedy patterns without confirming boundary behavior.
Workflow Notes
- Presets are included for common email/date/repeated-word patterns.
- Global flag affects whether single or multiple matches are reported.
- Group output helps debug capture behavior quickly.
Common Use Cases
- Validate pattern behavior before shipping production regex rules.
- Inspect capture groups and replacement behavior quickly.
- Debug edge-case match ranges in messy text data.
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FAQ
Can I preview replacement results?
Yes. Add replacement text to generate a replacement preview from the same pattern and flags.
What regex engine is used?
This route uses JavaScript RegExp behavior in your browser environment.