Leo's Lab
DevOps Tool Client-Side Only

Regex Tester

Test and debug regular expressions with live matching, group extraction, and replacement preview.

Regular Expression

/ /

Test String

Replace Mode

Use $1, $2, etc. for captured groups. $& for full match.

Privacy Guarantee

  • All regex testing happens locally in your browser
  • No data is sent to any server or stored anywhere
  • No network requests are made during testing
  • Source code is fully inspectable in your browser's developer tools