digitpdffile tools · on your device

Test regular expressions

Write a pattern, drop in sample text, watch matches highlight live — with groups, flags and a replace preview.

Runs on your device No uploads, ever Free, no account

How it works

  1. Enter your pattern

    JavaScript flavour — the same engine as your browser, so what you test here is what runs there.

  2. Paste sample text

    Matches highlight as you type. Capture groups are listed with their content.

  3. Try a replacement

    Use $1, $2 for group references and see the result before you commit it anywhere.

Questions people actually ask

Which regex flavour is this?

JavaScript (ECMAScript). Python, PCRE or .NET differences — lookbehind edge cases, possessive quantifiers — won't all translate, so test in the target language too.

Catastrophic backtracking?

A browser tab can still be hung by a vicious pattern; that risk is part of regex itself, not this page. Real text behaves.