Regex Tester

About This Free Online Regex Tester

Test regular expressions against text with real-time match highlighting. Enter your regex pattern and test string, and see matches highlighted instantly. Supports common regex flags (global, case-insensitive, multiline). Perfect for developers learning regex, debugging patterns, and validating expressions before using them in code.

Features of Our Regex Tester

Real-time regex matching with highlighting
Support for global, case-insensitive, and multiline flags
Shows match count and match details
Copy regex pattern to clipboard
100% private — browser-only processing

How to Use the Regex Tester

Using this tool is simple and requires no signup or registration. Follow these steps:

Enter your regex pattern in the pattern field.
Type or paste your test text in the text area.
Toggle flags (g, i, m) as needed.
Matches are highlighted in the text area. Match count is shown below.

Frequently Asked Questions About Regex Tester

What regex flags are supported?

Three flags are supported: g (global — find all matches), i (case-insensitive), and m (multiline — ^ and $ match line boundaries). These are the most commonly used flags in JavaScript regex.

Does this support all regex features?

This tester uses JavaScript's native RegExp engine, so it supports all JavaScript regex features including character classes, quantifiers, groups, lookaheads, and Unicode properties. Some advanced features like lookbehinds may not work in older browsers.

Why Choose Text Toolbox?

Text Toolbox provides free, private, and instant online text tools. Unlike other text utility websites that require signup accounts or send your data to servers, all our tools process your text entirely in your browser. This means your content never leaves your device — we cannot see it, store it, or share it. Our tools are fast, lightweight, and work on any device with a modern web browser.