Regex Tester
Test JavaScript regular expressions and inspect each match index.
Matches
Valid expression- toolat 15
- toolsat 38
About this regex tester
Regular expressions match patterns in text. They are useful for validation, search, extraction, log inspection, and text cleanup.
This tester uses JavaScript regular expressions, so syntax and flags follow the behavior of the browser runtime.
Common uses
- Check a pattern before using it in code
- Inspect match text and index positions
- Test flags such as g, i, and m
- Debug escaping issues in copied expressions
Notes
Complex expressions can be hard to maintain. Prefer clear patterns, test with representative examples, and be careful with user-provided regular expressions in production systems.