Test regular expressions against sample text, inspect matches, and verify common .NET regex options.
Test regular expressions against sample text, inspect matches, and verify common pattern options.
Match summary, first match preview, capture groups, and reusable pattern information.
The regex pattern compiled successfully with the selected .NET options and was executed against the provided test text.
The current pattern compiled correctly but did not produce any matches in the provided test text.
Use this tool to validate patterns before placing them into C# code, log parsers, monitoring rules, search filters, form validation, or automation workflows.
Practical reminders for testing and debugging regular expressions.
Use ^ and $ when you need full-line validation instead of partial matches.
Multiline affects line anchors, Singleline changes dot behavior, and IgnoreCase removes case sensitivity.
Keep groups purposeful so extraction logic stays readable and downstream parsing remains stable.
Typical reasons engineers use quick regex testing.
Validate emails, hostnames, IDs, and input formats before using them in applications or scripts.
Extract values from logs, config files, API payloads, and structured text.
Debug pattern behavior before using it in .NET code, pipelines, monitoring rules, or search filters.