How to test regex online for free

Testing a regular expression online means pasting a pattern and sample text into a tool that shows matches immediately. Done well, you iterate on flags and groups without redeploying code - and without uploading sensitive logs to a remote service.

Test regex with Jigglify (30 seconds)

1. Open the regex tester.
2. Enter the pattern without surrounding slashes (for example \w+@\w+\.\w+).
3. Toggle flags - use g for all matches, i for case-insensitive, and others as needed.
4. Paste a realistic test string (or click Sample).
5. Inspect matches, indices, and capture groups; copy the match list when ready.

What to look for in the results

• Match count - if you expected many hits but see one, enable the global flag.
• Capture groups - numbered and named groups should extract the right substrings.
• Highlighted preview - confirm you did not over-match with a greedy quantifier.
• Syntax errors - fix unbalanced parentheses or trailing backslashes first.

Why test locally in the browser

Sample data often includes emails, tokens, or customer strings. A client-side tester keeps that text on your machine while you refine the pattern. Jigglify uses the same JavaScript RegExp engine as most front-end and Node codepaths, so behavior stays close to production.

Tips before you ship the pattern

• Test empty strings, edge lengths, and Unicode if your app sees them.
• Prefer non-capturing groups (?:...) when you do not need the substring.
• Document required flags next to the pattern in code comments or config.

Test regex free with live matches and capture groups - private by default.
Open the free regex tester →

Related: What is a regular expression? · Common regex mistakes