Kafka & Stream Processing
Kafka fundamentals, KStreams, stateful processing, and exactly-once production deployments.
Kafka is the backbone of real-time data infrastructure at most large companies. LinkedIn processes over 7 trillion messages per day through Kafka. Mid-to-senior data engineers are expected to design partitions, handle exactly-once, and ship streaming apps that survive failures — not just produce and consume.
What you’ll be able to do
- Build Kafka producers and consumers with proper configuration
- Implement KStream and KTable processing topologies
- Design stateful stream processing with exactly-once semantics
- Deploy and optimize Kafka Streams applications in production
Curriculum
Phase 1: Kafka Foundations
Quick start and core Kafka concepts. The 2-minute first event plus the architectural primer every later module builds on.
Kafka Quick Start
Send an event to Kafka in 2 minutes, process it with Kafka Streams, and see real-time output. The fastest path from zero to a working streaming app — before any architecture or theory.
Kafka Fundamentals
Stream processing concepts, Kafka Streams architecture, your first streaming application, and the serde (serialization/deserialization) decisions that decide whether your topology survives production data.
Phase 2: Stream Processing
KStreams, stateful processing, and exactly-once. Where event flows graduate into joins, aggregations, windowing, and transactional guarantees.
KStream & KTable
KStream deep dive, KTable fundamentals, the three join patterns (KStream-KStream / KStream-KTable / KTable-KTable), and an event-enrichment pipeline built end-to-end on the join primitives.
Stateful Processing
State stores, aggregations + reduce, windowing strategies (tumbling / hopping / session), punctuators + scheduled callbacks, and custom processors for the patterns the DSL can't express.
Exactly-Once Semantics
Processing guarantees (at-most / at-least / exactly-once), Kafka transactions, EOS configuration, state-store consistency, failure recovery, and the production EOS considerations that the docs gloss over.
Phase 3: Production Deployment
Performance, deployment, and advanced patterns. The operational layer — topology optimization, HA deployment, monitoring, and the design patterns Kafka teams ship at scale.
Performance Optimization
Topology optimization, memory management, the Kafka Streams thread model + scaling strategy, metrics + monitoring, debugging + troubleshooting, and a performance-tuning checklist for production deployments.
Production Deployment
Deployment strategies, configuration management, high availability, graceful shutdown + upgrades, monitoring + alerting, security configuration, and the production checklist you'd defend in a launch review.
Advanced Patterns
Event sourcing, CQRS implementation, dead letter queues, testing strategies for streaming apps, schema evolution, and a capstone real-time analytics build that ships everything you've learned.
What you’ll build
- Producer + consumer with proper partition strategy and serde
- Stateful KStreams topology with joins, aggregations, and windowing
- Exactly-once pipeline with transactional commits + recovery
- Production-deployed streaming app with HA, monitoring, and event-sourcing capstone
This works in your local Kafka demo… but breaks the moment events hit production.
Without production-grade stream processing, you risk:
- Duplicate processing on rebalance because exactly-once was never wired correctly
- Topologies that work in dev and OOM on real partition skew at production volume
- State stores that silently corrupt after a broker restart with no recovery story
- Schema-evolution breaks because producers and consumers were never coordinated through a registry
What is Kafka & Stream Processing?
Apache Kafka is a distributed event streaming platform used for building real-time data pipelines and streaming applications. Kafka Streams is its client library for stream processing — enabling stateful transformations, joins, and aggregations. Used by LinkedIn, Uber, and Netflix to process trillions of events daily.
Why this matters in production
Kafka is the backbone of real-time data infrastructure at most large companies. LinkedIn processes over 7 trillion messages per day through Kafka. Production Kafka requires understanding partition strategies, consumer group management, and exactly-once semantics to avoid data loss or duplication.
Common use cases
- Building real-time event pipelines between microservices and data systems
- Implementing stream processing with KStreams for aggregations and joins
- Designing exactly-once delivery for financial transaction processing
- Creating CDC pipelines with Kafka Connect and Debezium
- Building real-time analytics dashboards with Kafka-powered data flows
- Deploying Kafka Streams applications with horizontal scaling
Kafka vs alternatives
Kafka vs RabbitMQ
Kafka is designed for high-throughput event streaming with replay capability. RabbitMQ is optimized for task queuing and routing. Kafka is the standard for data engineering; RabbitMQ for application messaging.
Kafka vs Pulsar
Kafka has a larger ecosystem and community. Pulsar offers built-in multi-tenancy and tiered storage. Most data teams choose Kafka for its maturity and tooling support.
Kafka vs Flink
Kafka handles event transport and simple stream processing. Flink provides advanced stateful processing with event-time semantics. Many teams use Kafka for messaging and Flink for complex processing.
Related skills
Why this skill matters
Kafka + stream processing is the data-engineering specialty that maps to streaming infrastructure roles. This skill proves you can ship event-driven systems that survive production — partition design, exactly-once, state management, HA deployment — the role LinkedIn, Uber, and Netflix pay top-of-band to staff their streaming platform teams.
Common questions about Kafka
What is Apache Kafka used for?
Kafka is used for real-time event streaming between systems. Data engineers use it to build event pipelines, CDC flows, stream processing applications, and real-time analytics infrastructure.
Is Kafka still relevant in 2026?
Kafka is the dominant event streaming platform. Confluent continues to innovate, and Kafka is deeply embedded in enterprise infrastructure. It remains the default choice for real-time data pipelines.
How long does it take to learn Kafka?
Basic producer/consumer patterns take 1-2 weeks. Kafka Streams with stateful processing and production deployment takes 6-8 weeks of focused practice.
Kafka vs Kafka Streams vs ksqlDB?
Kafka is the messaging platform. Kafka Streams is a Java/Scala library for stream processing. ksqlDB provides SQL-like queries over Kafka topics. Each serves a different abstraction level.
Do data engineers need Kafka?
Kafka knowledge is expected for mid-to-senior data engineers. Even if you use managed services like Confluent Cloud, understanding Kafka concepts is essential for designing reliable pipelines.
What is exactly-once in Kafka?
Exactly-once semantics ensures each message is processed precisely once, even during failures. Kafka achieves this through idempotent producers and transactional consumers.