Regex Tester

Regular Expression

Flags (g, i, m, etc.)

Test String

Match Preview (Highlighted)

Enter a regex and test string, then click "Test Regex".

Detailed Results

📦 Regex Tester Source Code $5.99

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What is a Regex Tester?

A regex tester lets you instantly check how a regular expression behaves against a specific string. Instead of guessing whether your pattern catches every edge case, you see live matches, groups, and positions right in the browser. It's an essential tool for validating input, parsing logs, or extracting data without writing throwaway scripts. Just type your pattern and test string to get immediate, detailed feedback.

How to Use

Enter your regex pattern in the top field, and optionally add flags like g, i, or m in the flags field.
Paste your test string into the text area — the string you want to search through.
Click "Test Regex" to see highlighted matches in the preview panel and a full breakdown of each match, including captured groups and index positions.

Frequently Asked Questions

Is my data safe when using this regex tester?

Absolutely. Every operation runs entirely inside your browser using local JavaScript. No data is ever sent across the network, stored on a server, or logged. You can test sensitive strings without worry.

Does this tool work without an internet connection?

Yes, it does. There are no external dependencies or backend calls, so the entire page functions perfectly offline once loaded. Save the HTML file locally and you'll always have a regex tester handy.

Can I test complex regex with lookaheads or Unicode?

Yes, the tool uses the native JavaScript RegExp engine, so it supports all standard features including lookaheads, lookbehinds, Unicode property escapes, and named groups. Your results will match what you'd see in Node.js or any modern browser console.

Disclaimer: This tool performs all operations locally in your browser. No data is stored, transmitted, or logged.