How Slack Rebuilt Its Backend for 10 Million Daily Active Users

In this episode, Lucas and Luna dive into the technical decisions behind Slack's backend overhaul as it scaled from a small team tool to a platform serving 10 million daily active users. They explore how Slack moved from a monolithic Ruby on Rails architecture to a service-oriented model using Java and C++, the critical choice of building its own message queue instead of relying on Kafka or RabbitMQ, and how the team tackled the 'unread counts' challenge that nearly broke the system. With specific examples like the Flannel service for real-time presence and the Vitess database sharding layer, this episode offers concrete lessons for CTOs and engineering leaders wrestling with growth. No vague platitudes — just the architecture decisions that kept Slack online during its hypergrowth phase. #Slack #BackendArchitecture #CTO #EngineeringLeadership #Scalability #Microservices #RealTimeMessaging #RubyOnRails #Java #CPlusPlus #Vitess #MessageQueue #Flannel #UnreadCounts #Business #Technology #FexingoBusiness #BusinessPodcast Keep every episode free: buymeacoffee.com/fexingo