devise_zxcvbn is a Ruby gem that integrates Dropbox's zxcvbn password strength estimation into Devise, a popular Rails authentication framework. It adds a `zxcvbnable` module that validates password strength during user registration or password changes, rejecting passwords below a configurable minimum score (default 4). The gem uses the `zxcvbn-rb` library to compute password strength, and optionally incorporates the user's email and custom weak words to improve accuracy. The codebase is small, well-structured, and includes RSpec tests. However, it has not seen significant updates since 2021, relies on an older version of the zxcvbn gem, and only tests against Ruby 2.6–3.0, indicating some technical drift. It remains a functional and reliable solution for Rails applications needing server-side password strength validation.