Regex Tester

Test JavaScript regular expressions with flags, match groups and find/replace. Debug patterns with live results and quick copy. Free and private.

Your data stays on your device. Nothing is uploaded.

Pattern
Test string
Replacement

How to Use the Regex Tester

1. Upload or paste

Enter or paste your input (text, token, JSON or options) into the tool.

2. Convert

Adjust settings if needed, then run the action to generate the result.

3. Download or copy

Copy the output or download it. Processing happens locally in your browser.

Features

Live matching

Matches are highlighted in the test string as you type, with total match counts.

All common flags

Toggle global, case-insensitive, multiline, dot-all, Unicode and sticky flags.

Find and replace

Enter a replacement string and preview the substituted result instantly.

Pattern explanation

Break down the pattern into a readable explanation and copy it with the regex.

Runs locally

Your patterns and text never leave your browser.

Free forever

No account or sign-up required.

FAQ: Frequently Asked Questions

It uses JavaScript regular expressions, the same engine found in all modern browsers and Node.js.

Yes, it is completely free and runs entirely in your browser.

Yes, enter a pattern, a test string and a replacement to preview the replaced output.

No, all matching and explanation happens locally on your device.