Traditional email servers were designed for a different era. They work great for small deployments but struggle at scale: Maildir breaks at 100k+ users, configuration changes require service reloads, and a single blacklisted IP blocks everyone on the server.

WildDuck takes a different approach. Built on MongoDB and Node.js, it treats email as a modern distributed systems problem. This talk explores the architectural decisions behind WildDuck and the lessons learned running it in production with 100,000+ accounts.