Good Fit
Where this tool usually helps most
Checking pattern matches before coding
Testing capture groups
Inspecting JavaScript-compatible flags quickly
Ready to use
Regex Tester
Test regex patterns with live match highlighting and group inspection.
Privacy-firstBrowser-sideNo upload
Updated 2026-05-18 · Reviewed 2026-05-23
Match summary
1 match found
const email = "hello@example.com";
const ticket = "BUG-2048";
const url = "https://www.freeutils.online/tools";
Captured groups
BUG-2048
Index 51
No captured groups
How to use
1
Enter a regex pattern and optional flags like g, i, or m.
2
Paste the text you want to test against.
3
Review highlighted matches and captured groups instantly.
FAQ
Does the tester support capture groups?
Yes. Each match can show any captured groups in the match details panel.
What happens if the pattern is invalid?
The tool shows the JavaScript regex error immediately so you can fix it.
Limits
Things worth knowing before you rely on the result
Behavior follows JavaScript regex rules, not every language runtime
Very large test text can be slower with complex patterns
Catastrophic backtracking patterns can still hang weaker devices
Example
A realistic example of what this page can help with
Extract ticket IDs
Input
Pattern: /TKT-(\d+)/g, Text: TKT-103 and TKT-204
Output
Matches: TKT-103, TKT-204; Groups: 103, 204
Handy for verifying capture groups before moving a pattern into code.
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How to Test Regex Safely in JavaScript
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Related Tools
Keep the workflow moving
Overview
Why this tool is useful
Regex testers are most useful when you want immediate feedback instead of writing a script from scratch. The main jobs are verifying matches, testing flags, and inspecting capture groups quickly.
A good tester should feel practical, not academic. People want to know whether it supports flags, groups, live matches, and JavaScript-compatible patterns before they rely on it.
Use Cases
Situations where it saves time
Validate extraction patterns before using them in production code
Debug JavaScript regex errors and edge cases
Test multi-line, global, or case-insensitive matching quickly
Practical Tips
Small details worth checking before you finish
Start with simple patterns before stacking multiple groups
Use anchors deliberately when matching full lines or inputs
If results look wrong, re-check active flags like g, i, and m
Next Steps
Useful follow-up tools for the same job
After using Regex Tester, many visitors naturally need a follow-up utility such as JSON Formatter & Validator, Base64 Encoder/Decoder, and Text Utilities. Keeping those nearby tools easy to reach makes the site more useful when one quick task turns into two or three.