Regex Tester — Real-Time Match Highlighting

Enter a regex and test string to see matches and capture groups highlighted in real time.

How It Works

  1. 1Upload your file by dragging it into the drop zone or clicking to browse.
  2. 2Adjust the quality slider to balance file size and visual fidelity (optional).
  3. 3Click Download to save your converted file.

About Regex Tester

Regular expressions are powerful but tricky to get right. This tool lets you enter a regex pattern and test string, then shows all matches highlighted in real time. Capture groups are displayed in a table with their index and value. Supports all JavaScript regex flags (g, i, m, s, u). Flags are toggleable with checkboxes. Everything runs in your browser.

Frequently Asked Questions

Which regex flavor does this use?

It uses JavaScript's built-in RegExp engine, which follows the ECMAScript specification. This is the same regex flavor used in Node.js, browsers, and most JavaScript frameworks.

What do the flag buttons mean?

g = global (find all matches), i = case-insensitive, m = multiline (^ and $ match line boundaries), s = dotAll (. matches newlines), u = Unicode.

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