Live Regex Tester, Highlighter & Cheat Sheet
Test regular expressions live with highlighted matches and groups. Free, runs in your browser.
In plain words: Type a pattern and some sample text to see what matches, highlighted as you type. Useful for checking a pattern before you use it in code.
How to Use Live Regex Tester, Highlighter & Cheat Sheet
- Enter your regular expression and flags (such as g, i, m, s, u) at the top, or click a preset (UK Postcode, Email Address, HTTPS URL, ISO Date with named groups, IPv4 Address).
- Type or paste your test string to see every match highlighted in real time, with its position and its numbered and named capture groups.
- Type a replacement (using $1, $2 or $<name>) in the Replacement field to preview the substituted output.
Real-Time Regular Expression Debugging Without Lag
Writing and verifying regular expressions shouldn't require guesswork. WeShoal's Live Regex Tester runs your pattern instantly in your browser, showing every match, its starting position, numbered groups ($1, $2) and named capture groups ((?<name>...)).
Handy Starter Patterns
One-click presets give you a starting point for UK postcodes, email addresses, HTTPS URLs, ISO dates (with named groups) and IPv4 addresses. They are practical, simplified patterns, so test them against your own data before relying on them for strict validation.