Regex tester
Free · no sign-upTest a regular expression against your text with live match highlighting.
Runs entirely in your browser — your data never leaves your device and nothing is stored. No sign-up.
Test and debug regular expressions against your own text, with matches highlighted as you type. This free regex tester supports JavaScript flags (g, i, m, s, u, y), shows every match with its position and captured groups, and tells you immediately if your pattern is invalid. It all runs in your browser — nothing is uploaded.
- ✓Live match highlighting as you type
- ✓All JavaScript flags: g, i, m, s, u, y
- ✓Match positions and captured groups listed
- ✓Clear error message for an invalid pattern
- ✓Runs in your browser — nothing uploaded
Who it's for
- Developers writing and debugging a regex
- Testing a validation pattern (email, phone, slug)
- Extracting data with capture groups
- Learning regular expressions by experiment
How it works
- 1Type your pattern between the slashes and set flags.
- 2Paste the text you want to test against.
- 3See matches highlighted and listed below.
- 4Refine the pattern until it matches what you want.
Frequently asked questions
Which regex flavour is this?+
JavaScript (ECMAScript) regular expressions — the same engine your browser and Node.js use, including flags g, i, m, s, u and y.
What do the flags mean?+
g = find all matches, i = case-insensitive, m = ^ and $ match each line, s = dot matches newlines, u = unicode, y = sticky.
Does it show capture groups?+
Yes. Each match lists its captured groups ($1, $2…) so you can see exactly what your parentheses capture.
Is my text uploaded?+
No. The pattern runs against your text entirely in the browser — nothing is sent to a server.
You may like
Some links may be partner links — how this works
Related tools
Format, validate and minify JSON in your browser.
Encode or decode Base64 text, UTF-8 safe.
Decode a JWT's header and payload in your browser.
Percent-encode or decode URLs and query strings.
Generate random UUID v4 identifiers in bulk.
SHA-1, SHA-256, SHA-384 and SHA-512 of any text.