Free Online Regex Tester & Validator
Test, debug, and validate regular expressions online with our free Regex Tester. Instantly see real-time matches, apply flags, and fine-tune your regex patterns in a secure browser environment. No installation, no data sharing—ideal for developers, QA, and students.
Runs in your browser
WebAssembly, no server
No signup required
Open and use instantly
Files stay private
Nothing leaves your device
How It Works
Enter your regex pattern and flags.
Paste your test string and click Test.
Key Features
- Real-time regex pattern testing and validation
- Instant match highlighting for test strings
- Supports all JavaScript RegExp flags and syntax
- No data leaves your browser—100% private
- Perfect for debugging, learning, and QA
About This Tool
Quickly prototype and debug regular expressions with live match highlighting and helpful error feedback. Toggle flags, inspect captured groups, and iterate on patterns in a safe, sandboxed environment. Runs entirely in your browser for privacy, making it ideal for learning, QA, and data-cleanup tasks.
Frequently Asked Questions
Yes, it uses the browser's RegExp engine.
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