zxcvbn

Tech stack & purpose

zxcvbn is a password strength estimator created by Dropbox that uses pattern matching and conservative estimation to evaluate password guessability. The tool recognizes and weighs common passwords, names, dictionary words, and patterns like dates, keyboard sequences, and leetspeak, returning an estimate of crack time and a strength score from 0 to 4 alongside actionable user feedback. Built in CoffeeScript and compiled to JavaScript via browserify and uglifyjs, zxcvbn is designed as an algorithmic alternative to traditional password composition policies, offering greater security, flexibility, and usability than rule-based approaches. The project has been ported to numerous languages including Python, Go, Rust, Java, C#, Ruby, and PHP, and is actively used by Dropbox across web, desktop, and mobile clients.

Languages

Contributors (top 30 of 37)

• Dan Wheeler324 commits
• studds4 commits
• Nathan Malkin4 commits
• Tom Sommer3 commits
• Antoine Grondin3 commits
• Luis Miranda3 commits
• Rohit Jha2 commits
• mrsendova2 commits
• Max Isom2 commits
• Zlatan Vasović2 commits
• Daniel Wolf2 commits
• Rian Hunter2 commits
• Giovanni Bajo2 commits
• 
  Nathan Rebours1 commits · 121 followers
• 
  Alex1 commits · 18 followers
• RoyboyNL1 commits
• chris varenhorst1 commits
• Chris Roby1 commits
• Leaky1 commits
• evilaliv31 commits
• Ronald Cheng1 commits
• Sandro Pasquali1 commits
• EricCS11 commits
• Aaron D. Campbell1 commits
• Ádám Lippai1 commits
• Yoav1 commits
• Chris Dosé1 commits
• Reed Loden1 commits
• Luke Taylor1 commits
• Brandon Amos1 commits