What If the Feed on Reddit Was More Than Just Posts
summary
Extends Reddit’s home feed to inject non-post units by running a parallel feed-experience pipeline that checks eligibility via an external service, builds candidates (community recommendations, announcements) with multi-pass ranking, then merges units into the post stream with static/dynamic slot rules and collision resolution. System handles 6k RPS, gives each block a 200ms timeout budget, never places no two experiences in a row, and adds observability counters for returned experiences and partial success rates.
AI-written summary · about
chapters (17)
- 0:00Introduction to Reddit
- 1:09What is Reddit's home feed
- 3:20Current feed architecture
- 5:57Why change the home feed
- 7:04Requirements for the change
- 9:13Initial solution ideas
- 12:22Introducing feed experience platform
- 13:34Changes in ranking platform
- 14:18Feed experience pipeline
- 17:08User eligibility for experiences
- 18:52Community recommendation block
- 22:04Feed experience vs organic post
- 22:49Feed injection merger
- 27:15Feed platform metrics
- 29:04Monitoring new metrics
- 31:37Current feed experiences
- 32:40Business impact and conclusion
related talks
41mThe Infinite Feed — No Jokes
20mRebuilding Reddit: A Case Study
23mRedesigning Reddit
46mFeed and Recommendation Architecture at VKontakte
32mScaling Developer Experience at Reddit, Airbnb and Amplitude
33mScaling at Large - Lessons learned rewriting Instagram’s feed
01h 14mFuture of social media what’s the recipe for pluralism, long term user value ..
27mModern Paging at Scale: StoreX + Compose