Regex Tester
Test regular expressions with live highlighting, capture groups, and flag toggles.
Runs entirely in your browser — files never uploaded
//g
Highlighted (2 matches)
Hello Alice and Bob, meet Charlie Davis at the office on Friday.
Matches & groups
- [0]@0Hello Alice
- $1Hello
- $2Alice
- [1]@26Charlie Davis
- $1Charlie
- $2Davis
How to use Regex Tester
- 1. Type a pattern. Use standard JavaScript regex syntax. Toggle flags below the pattern box.
- 2. Paste your test text. Matches are highlighted live as you type.
- 3. Inspect groups. Numbered and named capture groups show below for each match.
FAQ
Which regex flavor?
JavaScript regex (the same engine your browser uses for new RegExp). Almost identical to PCRE for common patterns; lookbehinds and named groups are supported.
What do the flags mean?
g = global (find all), i = case-insensitive, m = multiline (^/$ per line), s = dot matches newline, u = unicode, y = sticky.
Is my text uploaded?
No. Matching runs entirely in your browser using the native RegExp engine.
Can I test my regex on a huge file?
Yes, but very long inputs combined with backtracking-heavy patterns can hang the tab. Use anchors and possessive constructs for production patterns.
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