Test Regex Patterns Instantly
Free Online Regex Tester & String Utilities
Test regex patterns with real-time highlighting, multi-language support, and detailed match statistics. 100% client-side processing for maximum privacy.
When you need to turn parsed data into polished decks, PresentForge builds presentation-ready visuals in minutes, and TableForge formats your regex-matched results into beautiful tables.
Developer Tools
Essential utilities for developers, all free and privacy-first
Advanced Regex Tester
Test regular expressions with real-time highlighting, capture groups, and detailed match statistics.
Visual Regex Builder
Build regex patterns visually with an intuitive drag-and-drop interface.
Base64 Encoder/Decoder
Encode and decode Base64 strings with support for UTF-8 and binary data.
URL Encoder/Decoder
Encode and decode URLs with support for query parameters and special characters.
Hash Generator
Generate MD5, SHA-1, SHA-256, and other cryptographic hashes from text or files.
Text Compare
Compare two text blocks side-by-side with highlighted differences and detailed statistics.
Regex Cheat Sheet
Comprehensive regex syntax reference with examples and copy-paste patterns.
String Utilities
Case converter, text counter, UUID generator, random strings, and Lorem Ipsum generator.
Why RegexKit?
Built by developers, for developers
Real-Time Highlighting
See matches highlighted instantly as you type your pattern.
Multi-Language Support
Test patterns in JavaScript, Python, PHP, Java, Go, and Ruby.
Privacy-First
All processing happens in your browser. Your data never leaves your device.
100% Free
No registration, no ads, no limits. Free forever.
More Developer Tools
Explore our other professional developer utilities
CodeClean →
Modern developer code utilities for formatting and beautifying JSON, JavaScript, CSS, HTML, and more.
DiffMaster →
Professional code comparison tool with syntax highlighting, side-by-side diffs, and merge capabilities.
TextToolbox →
All-in-one text manipulation platform with case conversion, word counting, text cleaning, and analysis tools.
DataValidate Pro →
Developer data validation and conversion suite for JSON, XML, CSV, and API testing with schema validation.
Frequently Asked Questions
Common questions about regex patterns and our tools
What is a regular expression (regex)?
A regular expression is a sequence of characters that defines a search pattern. It's used for pattern matching within strings—finding, replacing, or validating text. For example, \d{3}-\d{4} matches phone patterns like "555-1234".
Is my data safe? Do you store my regex patterns?
Your data is 100% safe. All processing happens entirely in your browser—no data is sent to our servers. Your patterns, test strings, and results never leave your device. We use IndexedDB for local history storage (optional) and URL encoding for share links.
What's the difference between .* and .+?
.* matches zero or more characters (can match empty strings), while .+ matches one or more characters (requires at least one character). Use our Regex Tester to experiment with both patterns and see the difference!
Do I need to create an account to use RegexKit?
No! RegexKit is completely free with no registration required. All features are instantly available—just open the tool and start testing. No sign-ups, no emails, no limitations.
What regex flags are supported?
We support all common regex flags: g (global), i (case-insensitive), m (multiline), s (dotAll), u (unicode), and y (sticky). Toggle them easily in our Regex Tester interface and see real-time results.
How do I match email addresses with regex?
A basic email pattern is [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}. However, full RFC-compliant email validation is complex. Check our Regex Cheat Sheet for more examples and copy-paste patterns for common use cases.
Can I test regex for different programming languages?
Our Regex Tester currently uses JavaScript's regex engine, which covers most common regex syntax. While specific language features may vary slightly (like named groups or lookbehinds), the core patterns work consistently across JavaScript, Python, PHP, Java, Go, and Ruby.
What are capture groups and how do I use them?
Capture groups let you extract specific parts of a match. Wrap parts of your pattern in parentheses: (\d{3})-(\d{4}) captures area code and number separately. Our Regex Tester displays all capture groups with their values for easy debugging.