Frequently Asked Questions
How is this different from a regex tester?
This view focuses on debugging output and match indexing for quick troubleshooting.
Which flags are supported?
JavaScript flags like g, i, m, s, u, and y are supported.
Is input data uploaded?
No. Everything runs locally in your browser.
Example input/output
Input: Pattern: (\w+)@(\w+) / Input: user@domain
Output: Match 0: user@domain / Group 1: user / Group 2: domain
How it works
This tool runs the regex against the input and returns the full match result object, including match index, input string, captured groups (by index and name), and indices if the d flag is set. Processing runs in your browser.
Common use cases
- Step through regex execution to understand why a pattern fails to match
- Visualise match attempts and backtracking for complex expressions
- Debug named capture groups and alternation in regex patterns