Regex Cheat Sheet
Online regex cheat sheet with syntax reference, common patterns, and live matching test
Live Test
Enter a pattern to start testing
Basic Syntax
Character Classes
Quantifiers
Groups & Backreferences
Assertions
Common Patterns
Guide
Regex Cheat Sheet provides practical syntax references and live matching so you can quickly validate patterns during development and data processing.
Key Features
- Built-in references for syntax, classes, quantifiers, groups, assertions, and common patterns.
- One-click apply from cheat items into the test pattern input.
- Live match output with item list and match positions.
- Flag switching and syntax error feedback for faster debugging.
How To Use
- Enter a regex pattern and choose flags.
- Paste text in the test textarea.
- Check matched items and positions in results.
- Use any cheat pattern with one click.
Use Cases
- Form rule validation
- Log filtering and issue locating
- Text cleaning and data extraction
- Regex debugging during development
Tips
Performance
- Prefer specific classes over broad patterns like .*.
- Avoid nested quantifiers that trigger heavy backtracking.
- Use non-capturing groups (?:) when capture is unnecessary.
- Anchor patterns with ^ and $ when possible.
Debugging
- Build complex patterns from simple parts step by step.
- Test grouped fragments before final composition.
- Double-check escaping in both regex and string context.
- Compare behavior under different flags.
FAQ
- Why no result: verify pattern, flags, and text scope.
- Why syntax error: check escaping and group/assertion structure.
- Can it do replace now: current version focuses on matching and references.
- Will input be uploaded: no, processing runs locally in browser.
Privacy
Your regex pattern and test text stay in browser. This tool does not upload your input.