Case Study: Discord scales to 2.4M concurrent users, cuts cloud costs, and protects websockets with Cloudflare

Discord - Customer Case Study

Discord is a voice and text communication app for PC gamers aiming to be the de-facto standard; by July 2016 it had 2.4 million concurrent users and over 25 million registrations. As it prepared for rapid growth, Discord needed to scale its infrastructure affordably and improve performance by moving off a single-homed setup to a global CDN, while also protecting its websockets-based traffic from frequent DDoS attacks that strained engineers and required costly HAProxy/DNS failover hardware.

Discord implemented Cloudflare in August 2015 (when it had ~25,000 concurrent users), leveraging 100+ PoPs to serve over 2PB/month from the edge and interconnect with Google Cloud. The result: secure, reliable handling of websocket spikes up to 2 million events/second, growth to 2.4M concurrent users, and major cost savings—about $100,000 monthly on Google Cloud and $100,000 annually on hardware—letting the team focus on the product.

Discord

Stanislav Vishnevskiy

CTO