Idempotent consumers, without the ceremony
What actually happens when the same message arrives twice, and the smallest set of changes that makes a consumer safe to retry.
Notes from building backend systems: what I designed, what broke, and the reasoning I wish I had written down the first time.
Topics
Not tutorials. Working notes: what I tried, what it cost, and what I would tell myself before starting.
Agents, LLMs, RAG and AI architecture — what I build, test and break.
Distributed systems, databases, messaging, caching and scaling.
Working references from Java, Spring, PostgreSQL, Kafka, Redis and Kubernetes.
Full write-ups from problem to trade-offs, with the diagrams to match.
Latest
Newest first. Some are finished thoughts, others are still moving.
What actually happens when the same message arrives twice, and the smallest set of changes that makes a consumer safe to retry.
Not a benchmark. A comparison of the questions each one makes you answer: about ordering, replay, consumers and who owns the offset.
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I am always up for a conversation about architecture, trade-offs, or a bug that refuses to die.
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