Regular Expressions 101

Please wait while the app is loading...

Regular Expressions 101

@regex101DonateSponsorContactBug Reports & FeedbackWikiWhat's new?

Save & Share

  • Save Regex
    ctrl+s
  • Update Regex
    ctrl+⇧+s

FlavorNeed help selecting flavor?

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET (C#)
  • Rust

Function

  • Match
  • Substitution
  • List
  • Unit Tests (3)
Sponsors
An explanation of your regex will be automatically generated as you type.

Regular Expression

Regex Versions

/

Delimiters

/
i

Regex Flags

Unit Tests

given the string CAT assert that regex does match
given the string 99 red baloons assert that regex does match
given the string elbow macaroni assert that regex does not match

Tools and Filters