Free Regex Tester – Test Regular Expressions Online
Test regex patterns with real-time highlighting.
ToolCraftr is a free regex tester that validates and tests regular expressions in real-time. Our regex validator shows match highlights, capturing groups, and pattern explanations. Perfect for developers debugging regex patterns.
Who is this regex tester for?
Software Developers testing regex patterns for validation, parsing, and text processing.
Data Scientists extracting structured data from unstructured text using regex.
DevOps Engineers writing regex for log parsing and monitoring alerts.
Students learning regular expressions and testing pattern-matching syntax.
Key Features
Real-Time Testing
See matches highlight instantly as you type our regex pattern. Immediate feedback on every change.
Match Highlighting
All matches are visually highlighted in your test string with different colors for easy identification.
Capturing Groups
View all capturing groups separately with their matched values. Essential for complex patterns.
Pattern Explanation
Human-readable breakdown of what your regex pattern does, part by part.
Regex Flags
Toggle global (g), case-insensitive (i), multiline (m), and other flags easily.
100% Private
All regex testing happens in your browser. No patterns or data sent to servers.
Understanding regex patterns
Regular expressions are patterns used to match character combinations in strings. They're incredibly powerful for validation, searching, and text manipulation.
Our tester uses JavaScript regex engine, which supports lookaheads, lookbehinds, named capturing groups, and Unicode property escapes.
Common Questions
What regex flavors are supported?
Our regex tester uses JavaScript regex engine. It supports ECMAScript regex syntax including lookaheads, capturing groups, and all standard flags (g, i, m, s, u, y).
Can I see capturing groups?
Yes! All capturing groups are displayed separately, showing exactly what each group matched. This helps debug complex patterns.
Does it explain regex patterns?
Yes. We provide human-readable explanations of regex patterns, breaking down what each part of the expression does.
Is my test data stored?
No. All regex testing happens entirely in your browser. We do not store, log, or transmit any patterns or test strings.