Developer Tools
Regex Tester
Rates & guidance reviewed
Regular expressions are powerful for validation, search and text extraction — and easy to get wrong. This free regex tester lets you try patterns against sample input with live match highlighting.
Use standard JavaScript RegExp syntax and flags (g, i, m, s, u, y). Matches update as you type so you can iterate quickly while writing patterns for forms, logs or parsers.
All testing is client-side. Complex patterns on huge texts may be slow; keep samples reasonably sized.
Interactive tool
Without surrounding slashes
2 matches
Highlighted matches
| # | Match | Index |
|---|---|---|
| 1 | freeuktools@aivora.digital | 14 |
| 2 | support@freeuktools.com | 44 |
How to use this tool
- Enter your regular expression (without surrounding slashes).
- Select flags such as global (g) or case-insensitive (i).
- Paste the text to test against.
- Review match list and highlighted results.
JavaScript regex tips
Flags matter: g finds all matches, i ignores case, m changes ^ and $ to line boundaries, s lets the dot match newlines. Enter the pattern without surrounding slashes — those are only for literals in source code.
Pathological patterns with nested quantifiers can run very slowly (catastrophic backtracking). Keep test strings short while experimenting, and prefer clearer patterns over clever ones when validating user input.