Zeitwerk is an efficient and thread-safe code loader for Ruby.

Given a conventional file structure, Zeitwerk is able to load your project's
classes and modules on demand (autoloading), or upfront (eager loading).  You
don't need to write `require` calls for your own files, rather, you can
streamline your programming knowing that your classes and modules are
available everywhere.  This feature is efficient, thread-safe, and matches
Ruby's semantics for constants.

Zeitwerk is also able to reload code, which may be handy while developing web
applications.  Coordination is needed to reload in a thread-safe manner. The
documentation below explains how to do this.