Free tool

Regex Tester

Test a regular expression against any string with live-highlighted matches and capture groups - powered by your browser's native engine, nothing leaves the page.

Pattern

Regular expression

//g

Flags

g global i ignore case m multiline s dotAll

Test string

Highlighted

2 matches

Matches & groups

Match 1 @ 14: hello@example.com
  group 1: hello
  group 2: example
  group 3: com
Match 2 @ 35: support@feature.dev
  group 1: support
  group 2: feature
  group 3: dev

Regex, without the guesswork

A regular expression is a compact pattern language for finding and extracting text - validating an email, pulling a ticket ID out of a branch name, or parsing a log line. The hard part is rarely the idea; it is confirming the pattern does exactly what you expect on real input. This tester compiles your pattern with the browser's native RegExp and highlights every match as you type, so you can iterate in seconds instead of round-tripping through code.

Because it uses the same engine your JavaScript and Node runtime ship with, what you see here is what you get in production - including flag behavior, capture groups, and named groups written as (?<name>…). Invalid patterns fail gracefully with the exact engine error, so a stray unmatched bracket never leaves you guessing.

Small utilities like this are the same discipline we bring to shipping software: tight feedback loops and outcomes you can verify. If that resonates, explore our other developer tools - conventional commit builder, cron expression builder, and gitignore generator - or see the full tools directory.

Frequently asked questions

Your browser's native JavaScript RegExp. That means results match exactly what you get in Node.js and browser code - the same engine, the same flags, the same edge cases. There is no server round-trip.

g (global) finds every match rather than just the first. i makes matching case-insensitive. m (multiline) makes ^ and $ match line boundaries. s (dotAll) lets . match newline characters.

Each match lists its numbered capture groups in order, plus any named groups written as (?<name>...). Empty or optional groups that did not participate are shown as blank so positions stay aligned.

Measure what you ship

Fast, verifiable tools are how we work. FeatureFactory helps engineering teams plan, build, and measure AI web development - with outcomes you actually own.

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