Regex Tester

Write a regular expression and test it against any string — live results as you type.

Pattern

Flags

g i m s

Test String

Regex Testing Strategy

Build patterns iteratively with realistic sample text. Testing against edge cases prevents false matches and expensive production bugs.

Start simple, then add groups and quantifiers step by step.
Check greedy and non-greedy behavior on multiline input.
Validate capture groups before wiring extraction logic.

Related tools: Text Escape, Text Analyzer, JSONPath Tester.

Regex Tester FAQ

Why does a pattern match too much text?

Greedy quantifiers can consume more than expected without clear boundaries.

Do regex engines behave the same everywhere?

No. Feature support and flags vary by language and runtime.

How can I test multiline input reliably?

Enable the proper flags and include representative line breaks in test samples.