What the regex tester does
Paste a regular expression and a test string, and this tester highlights every match live as you type, breaks out capture groups, and lets you toggle flags (global, case-insensitive, multiline). Common presets — email, URL, IP address, date — give you a working pattern to adapt instead of starting from scratch. It runs in your browser, so nothing you paste is sent anywhere.
How to test a pattern
- Enter your pattern (without the surrounding slashes) and pick your flags.
- Paste sample text; matches highlight instantly.
- Inspect the numbered capture groups to confirm you're extracting the right parts.
Why test regex before you ship it
Regex is easy to get subtly wrong — a greedy quantifier that over-matches, an unescaped dot, a group that captures too much. Testing against real sample data, including the edge cases (empty strings, unicode, multiline input), catches these before they reach production, where a bad pattern silently drops or mangles data.
