Test regular expressions against input text with real-time match highlighting. Shows match count, positions, and named capture groups. Supports all standard flags.
Open Regex Tester → free, no sign-inRegular expressions are powerful but notoriously difficult to write correctly — a misplaced character can match nothing when you expect everything, or match too much when you expect precision. The Regex Tester validates your pattern against test input in real time, highlighting every match and showing exact positions. Supports flags (global, case-insensitive, multiline) and shows named capture groups.
Developers writing validation logic, text processing scripts, or search-and-replace operations who need to test their regex before using it in production code.
No tutorials. No learning curve. Open it and get started.
No server uploads. Shows match positions alongside the highlighted text — useful for understanding exactly what was matched when working with complex patterns.
Completely free. No trial period. No premium tier for basic functionality. No account required. Use it as often as you need.
One job, done well. Regex Tester was built to solve a specific problem cleanly. No feature bloat, no ads, no distractions.
What regex flavour is used?
JavaScript RegExp — the most widely used web regex implementation.
What does the global flag do?
Without /g, only the first match is found. With /g, all matches are returned.
How do I test a named capture group?
Use (?
What is a lookahead?
(?=pattern) matches a position followed by pattern without consuming characters. (?!pattern) is negative lookahead.
Why does my regex work in JavaScript but not here?
Check flag settings — differences in global/multiline flags are a common cause.
Free. Instant. No sign-in. Open it and get the job done.
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