- Validation, Explain and DebuggingCheck that a pattern compiles, read the error, inspect its groups, explain it in plain English and see it in the debugger.
- Match TracingSee which construct consumed which characters, or exactly where and why a pattern stopped matching.
- Highlighting MatchesMark every match and group capture in a text, as ANSI colors for terminals, HTML for web pages or brackets for tests and logs.
- Railroad and Mermaid DiagramsDraw any pattern as a self-contained SVG railroad diagram or a Mermaid flowchart for docs, pull requests and code review.
- Backtracking ProfilerCount the steps and backtracks a pattern costs on a real input, see which construct does the work, and guard that cost in tests.
- Regex CoverageFind out which alternation branches, optional parts and repetition limits your test inputs never exercise.
- Test Data GenerationGenerate strings a pattern matches and near misses it rejects, reproducibly, for tests and fuzzing.
- Property TestingCheck that a property holds for every string a pattern generates, and shrink a failure to the smallest input that still breaks it.
- xUnit Theory Data[MatchingData] and [NonMatchingData] feed xUnit v3 theories with reproducible strings a pattern matches, or near misses it rejects.
Test and Debug
Explain, trace, highlight, draw and profile patterns, and test them with coverage, generated data and properties.