Regex Tester & Cross-Language Converter
Test regular expressions with live highlighting, get AI explanations, and convert between JavaScript, Python, Go, Rust, PHP, and Java.
How It Works
Enter Your Regex
Type your regex pattern and toggle flags (g, i, m, s, u, y). Choose from common presets like email, URL, or date patterns.
Test & Explore
Paste your test string and see matches highlighted in real-time. Inspect capture groups, named groups, and match positions.
Explain & Convert
Get an AI-powered plain English explanation, or convert your pattern to Python, Go, Rust, PHP, or Java with syntax notes.
Why Use This Tool
Live Match Highlighting
See matches highlighted instantly as you type no button clicks needed for testing.
AI-Powered Explanation
Get a plain English breakdown of what your regex does, component by component.
Cross-Language Conversion
Convert regex between JavaScript, Python, Go, Rust, PHP, and Java with syntax difference notes.
Built-in Cheatsheet
Quick reference card with character classes, quantifiers, anchors, groups, and flags always one click away.
FAQ
What is a regular expression?
A regular expression (regex) is a pattern that describes a set of strings. It's used for searching, matching, and manipulating text in programming languages. For example, \d+ matches one or more digits.
How does the AI explanation work?
The AI analyzes your regex pattern and generates a plain English explanation of each component character classes, quantifiers, groups, and assertions. It's especially helpful for understanding complex patterns written by others.
Why do regex patterns differ between languages?
Different programming languages implement regex engines with slightly different syntax. For example, JavaScript uses (?<name>) for named groups while Python uses (?P<name>). The global flag "g" in JavaScript has no equivalent in most other languages they use functions like findall() instead.
Is the regex testing secure?
Yes. All regex testing happens in your browser your test strings are never sent to a server. Only the AI explanation and cross-language conversion features use server-side processing, and patterns are never stored.
Does it protect against catastrophic backtracking?
Yes. The tester includes a 2-second timeout and caps matches at 10,000 to prevent patterns with catastrophic backtracking from freezing your browser.
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