BBC News: 2.5 million push notifications per minute.
In 2012, the BBC needed push notifications for BBC News and BBC Sports, their flagship mobile apps running on tens of millions of devices. The backend had to handle the full installed base from day one, send as many pushes as the news demanded with no per-notification pricing, and beat every competitor to the lock screen. The target: at least 2.5 million notifications per minute.
ProcessOne built the entire system from scratch in three months: a scalable backend, management interface, editorial API, and sophisticated topic-based subscriptions so users could follow a specific football team, choose exactly which events to be notified about, and never receive a duplicate.
The system ran for years, delivering millions of pushes every single day to tens of millions of BBC News and BBC Sports users on iOS and Android.