Regex Tester
Test regular expressions against sample text, inspect matches, and verify common .NET regex options.
Input
Test regular expressions against sample text, inspect matches, and verify common pattern options.
Result
Match summary, first match preview, capture groups, and reusable pattern information.
What this means
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.
Common presets
Regex quick guide
Practical reminders for testing and debugging regular expressions.
Anchor deliberately
Use ^ and $ when you need full-line validation instead of partial matches.
Flags change behavior
Multiline affects line anchors, Singleline changes dot behavior, and IgnoreCase removes case sensitivity.
Capture only what matters
Keep groups purposeful so extraction logic stays readable and downstream parsing remains stable.
Common use cases
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.