Skip to content

Regex Tester

Test regular expressions with live matches and flag controls.

Flags

Valid regex3 matches
user_123
Start index: 0
admin_456
Start index: 37
guest_12
Start index: 72

Regex Quick Tips

  • Use \\d for digits, \\w for word chars, and \\s for whitespace.
  • Add i for case-insensitive matching and m for line-based anchors.
  • All matching happens locally in your browser for privacy and speed.
  • 100% free — no account needed
  • Runs in your browser
  • Nothing is uploaded

Frequently asked questions

Which regex flags are supported?

The Regex Tester supports common JavaScript flags including global, ignore-case, multiline, and dotall.

Can I see match positions?

Yes. The tool lists each match and its start index in the input text.

Does this run in the browser?

Yes. Pattern testing runs locally in your browser using JavaScript regex behavior.

More developer tools

Folder Structure Generator

Build folder structure diagrams, ASCII directory trees, and file tree visualizations for READMEs and docs.

.gitignore Generator

Generate merged .gitignore rules for your stack with one click.

JSON to TypeScript Interface

Convert JSON into TypeScript interfaces with inferred nested types.

Text to Slug Converter

Convert titles and phrases into clean SEO-friendly URL slugs.

UTM Builder

Build campaign URLs with UTM parameters for analytics tracking.

JSON Formatter & Validator

Validate, format, and minify JSON directly in your browser.