Pub/Sub
A messaging pattern where publishers send messages to topics, and subscribers receive messages from topics they care about. Publishers don't know who's listening.
What is Pub/Sub?
A messaging pattern where publishers send messages to topics, and subscribers receive messages from topics they care about. Publishers don't know who's listening.
Pub/Sub is a intermediate-level concept that sits in the Messaging & Event Systems area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "Pub/Sub" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
Learn Pub/Sub in depth
Full interactive lesson with diagrams, code examples, real-world references, and a quiz.
Open the Pub/Sub lessonRelated lessons
Lessons that touch on Pub/Sub as part of a larger topic.
Pub/Sub Pattern
One publisher, many subscribers, the pattern that powers event-driven systems at scale
intermediate · messaging event systems
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The Swiss Army knife of caching, data structures, persistence, clustering, and why nearly every major tech company runs Redis
foundation · caching strategies
See also
Related glossary terms you might want to look up next.
Message Queue
A buffer that stores messages between producers and consumers. Messages are processed one by one, in order. Think of it as a to-do list for your services.
Kafka
A distributed event streaming platform that handles millions of events per second. Used by LinkedIn, Netflix, and Uber for real-time data pipelines.
Event Sourcing
Storing every state change as an immutable event instead of just the current state. You can rebuild any past state by replaying events.