A regex tester lets you write and debug regular expressions interactively. Instead of running your code, waiting for output, and guessing what went wrong, you can see exactly which parts of your test string are matched and inspect each capture group as you refine your pattern.
This free regex tester uses JavaScript's native RegExp engine, so the behavior matches exactly what you would get in a browser or Node.js environment. You can toggle flags including global (g), case-insensitive (i), multiline (m), and dotAll (s). Each match is highlighted in the test string, and a detailed list shows every match along with its capture groups and positions. A reference sidebar provides ready-to-use patterns for common tasks like validating emails, URLs, phone numbers, IP addresses, and dates.
All processing happens locally in your browser. Your patterns and test data are never sent to a server, making this regex tester safe for testing against sensitive content. There are no usage limits and no account required.