Regex Tester
Test and debug regular expressions with real-time matching.
Regex Tester
Test regular expressions against text.
Guide
How to Use the Regex Tester
Get the most out of this free tool.
Write and test regular expressions with real-time matching feedback. Enter your regex pattern and test string to see all matches highlighted. Shows match groups, positions, and captures. Supports common flags (global, case-insensitive, multiline). Essential for developers working with pattern matching.
Tips for Best Results
- Be specific with your inputs for more accurate results.
- Try different variations to compare outcomes.
- Use the copy button to save or share results.
Why This Tool Matters
This checker helps you save time, make data-driven decisions, and improve your business performance without expensive software or technical skills.
FAQ
Regex Tester FAQ
Common questions answered about this free tool.
What regex engine is used?
We use JavaScript's RegExp engine (ECMAScript). Features like lookahead, lookbehind, named groups, and Unicode properties are supported.
Can I test regex against large texts?
Yes. Test strings up to 100KB are supported. Performance may vary with complex patterns against large inputs.
Are these developer tools free?
Yes, all our developer tools are completely free with no usage limits. Use them as much as you need for your development work.
Do you store my code or data?
No. All processing happens client-side in your browser. Your code and data never leave your device.
What is the maximum input size?
Most tools handle inputs up to several megabytes. For JSON formatter and validators, very large files (over 10MB) may cause slower performance.
Can I use these tools in my CI/CD pipeline?
These tools are designed for browser use. For programmatic access, we recommend using dedicated CLI tools or libraries.
Are the formatters configurable?
Yes, formatters typically include indentation settings (spaces vs tabs). JSON formatter supports different indentation levels.
What encoding standards are supported?
Base64 encoder/decoder supports standard Base64 with padding. URL encoder follows RFC 3986 encoding standards.
Can I validate JSON against a schema?
The JSON Validator checks syntax validity and structure. For JSON Schema validation, you would need specialized tools.
Are the CSS generators production-ready?
Yes, all generated CSS follows W3C standards and works in all modern browsers. Browser prefixes are included where needed.
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