# How Patreon processes millions of notifications without timeouts Scaling with a two-stage fanout architecture in a 13-year-old codebase. - **Source:** [programming](https://brifing.si/source/21f413d8-a401-41ca-83b1-904b87bb8257) - **Published:** 2026-07-14 - **Topic:** [Software & Engineering](https://brifing.si/c/engineering) - **Original article:** - **On Brifing:** https://brifing.si/s/06a982aa-1e75-4e2c-9edd-68767e060a32 ## Background Patreon sends billions of notifications annually. However, as large creators' audiences grew, a legacy system for generating recipient-specific notifications began consistently timing out. This negatively impacted user experience and required immediate attention. ## Architectural overhaul The engineering team developed a two-stage fanout architecture to solve this. Notifications are first grouped, then processed through separate channels for email, push, and in-app notifications. This significantly improved system efficiency and reliability. ## Improved observability The new system provides detailed monitoring at every stage. Notification delivery times, durations, and success rates can now be tracked in real-time. This enhanced visibility has dramatically improved operational efficiency and troubleshooting capabilities. ## Migration process Transitioning over 200 notification types in a 13-year-old codebase required substantial engineering effort. The team carefully analyzed each notification type, resolving compatibility issues to ensure a seamless migration with zero downtime. ## Performance gains The new system now processes millions of notifications without timeouts. Response times have significantly improved while resource usage has been optimized. This infrastructure upgrade supports Patreon's continued growth and scalability. ## Key takeaways This project serves as an important case study for modernizing legacy systems in growing platforms. The phased architectural approach and detailed migration planning provide valuable insights for teams facing similar technical challenges at scale. ## Sources covering this story - https://www.reddit.com/r/programming/comments/1uwj90b/how_we_rebuilt_our_notification_platform_to/ — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._