Live Regex Tester & AST Library
Utilix Live Regex Tester is an interactive regular expression debugger that highlights capture groups in real time, translates every regex token into plain English, and generates ready-to-paste JavaScript, Python, and Go snippets.
How to Test Regular Expressions and Understand Regex Tokens in Plain English?
Enter your regular expression pattern and test string in Utilix Live Regex Tester (or select a 1-click preset like Email, IPv4, or URL) to immediately view matched capture groups, character indices, and a token-by-token plain-English AST explanation.
How to use Live Regex Tester & AST Library
- Enter Pattern or Pick a Preset: Type a regex pattern with flags (g, i, m) or choose Email, IPv4, URL, or Password presets.
- Inspect Real-Time Capture Groups: View every match index and numbered capture group against your test string.
- Copy Plain-English AST or Code Snippet: Review the token breakdown or copy generated JS, Python, or Go regex code.
Frequently asked questions
How does the plain-English Regex Explainer work?
Utilix parses your regular expression into individual lexical tokens (anchors, character classes, quantifiers, groups) and describes the exact matching rule for each token.
What happens if I accidentally write a catastrophic backtracking regex?
Utilix includes a safety iteration guard so zero-length or runaway matches never freeze your browser tab.
What presets are included in the 1-click library?
Email Address, IPv4 Address, Strong Password, HTTPS URL, Credit Card Number, and ISO-8601 Date.
Can I export ready-to-use code for Python or Go?
Yes, switch between JavaScript, Python (re.findall), and Go (regexp.MustCompile) snippets in the output panel.
Are flags like global (g), case-insensitive (i), and multiline (m) supported?
Yes, you can toggle flags interactively and see results update on every keystroke.