Free Regex Tester Online - Fast & Private Web Utility
Test regular expressions with live highlighting and capture groups.
Runs entirely in your browser - your files are never uploaded
What is Regex Tester?
Regex Tester is a free, web-based utility designed for instant, local developer tools tasks. It allows users to compute, format, convert, or edit data directly in their browser without installing software or registering an account.
- 100% Free & Unlimited Usage
- 0% File Uploads (100% Client-Side Privacy)
- Instant Real-Time Calculations
- Mobile, Tablet & Desktop Compatible
How to use Regex Tester
Select or Enter Input
Provide your source file or type your values into Regex Tester.
Configure Settings
Adjust parameters, formatting options, or units in real-time.
Get Instant Output
Download the final processed file or copy the generated output.
Features & Overview of Regex Tester
Type a pattern and some sample text to see every match highlighted instantly, along with a numbered table of matches, their index and each capture group. Invalid patterns show the engine's error message rather than failing silently.
Toggle the global, ignore-case, multiline, dotAll, unicode and sticky flags, then use the replacement box to preview a String.replace result with $1 style backreferences before you put it in your code.
Frequently Asked Questions about Regex Tester
Answers to common questions regarding Regex Tester features, data privacy, and usage.
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