Pub/Sub Architecture
Slack + Online Chess
About this session
Deep dive into Pub/Sub and event-driven architecture through two real system design interview questions: designing Slack real-time messaging and an Online Chess platform.
Lecture: author of showoffer
Tony
Engineer Manager
Engineering Manager: Over 12 years of industry experience with 6 years in engineering leadership, building and scaling tech infrastructure teams that deliver end-to-end large-scale distributed systems.
Reviews
Reviewer 0JSF
May 10, 2026Came in for the Chess design and stayed for the trade-off discussions. The way ordering guarantees were tied back to user-visible behavior (move reconciliation) was the clearest explanation I've seen. Definitely recommend.
Reviewer 173K
May 10, 2026The Slack walkthrough finally made fan-out vs fan-in click for me. Loved how the coach traced a single message all the way from publish to subscriber and showed where backpressure usually breaks. Would recommend to anyone prepping for senior-level system design rounds.
Reviewer 1YCR
May 9, 2026Strong session. The deep-dive into how Slack handles presence updates and message ordering was worth the price alone. The reference solution for the chess matchmaking variant was a nice bonus.
Reviewer 02KW
May 8, 2026Very interactive. The poll-driven Q&A kept the pace high and the coach didn't dodge the harder questions on at-least-once vs exactly-once delivery. Solid 60 minutes — recommend pairing it with the Pub/Sub design pattern article beforehand.
Reviewer 1P11
May 7, 2026Good blend of pattern-level theory and concrete examples. I left with a much better mental model for when to reach for Pub/Sub vs a queue. Recording was useful for re-watching the partitioning section.
Reviewer 0TU0
May 6, 2026Recommend. The coach pushed back on lazy answers in the Q&A and that feedback alone was worth attending live. Going to apply the same framing in my next mock interview.
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