Text & Code Live tool
Regex Tester
Test JavaScript regular expressions against local text and inspect matches, indexes, capture groups, and flags.
Tool Flow
01 Input
02 Process
03 Output
Tool Guide
About the Regex Tester
Use the Regex Tester to run JavaScript regular expressions against local text and inspect exactly what matched. It shows match counts, zero-based indexes, capture groups, named groups, and invalid pattern or flag errors.
Common uses
- Test JavaScript regex patterns before using them in code.
- Check capture groups and named groups against realistic sample text.
- Debug flags like global, multiline, case-insensitive, and dotAll.
- Copy match JSON for issue reports or test fixtures.
Browser workflow
- 01 Enter a JavaScript regex pattern and optional flags.
- 02 Paste or type the text to test against.
- 03 Review match indexes, values, and capture groups.