Uploaded May 2020 | Updated September 2026, 1 day ago

---

In this video, Facebook Software Engineer Kevin Wu Won chats with me about an exciting feature he's been working on over the past couple of months: Messenger Rooms. Built on top of React, Relay, Flow, GraphQL, and Hack, Messenger Rooms is a huge video conferencing feature that took the concerted effort of dozens of engineers to launch.

Interesting Facebook Engineering blog post: engineering.fb.com/web/facebook-redesign

AlgoExpert: algoexpert.io/clem
SystemsExpert: systemsexpert.io/clem
My LinkedIn: linkedin.com/in/clementmihailescu
My Instagram: instagram.com/clement_mihailescu
My Twitter: twitter.com/clemmihai

Prepping for coding interviews or systems design interviews? Practice with hundreds of video explanations of popular interview questions and a full-fledged coding workspace on AlgoExpert - algoexpert.io - and use the promo code "clem" for a discount on the platform!