This is a session I gave on ServerlessDays Milano on October 21st, 2025.
One of the biggest challenges in serverless development is the gap between how developers expect AWS services to behave and how they actually work. In many cases, this mismatch can lead to data loss or unexpected results. We'll begin with DynamoDB'deceptively simple, yet packed with gotchas that can lead to silent data loss or misleading results. Then we'll examine pitfalls in event-driven architecture: from misconfigured queues and dead-letter queues to misunderstood EventBridge behaviors, stream processing and more. Then we'll zoom out to explore serverless design patterns that seem fine at first'but can quietly cause issues like event duplication, out-of-order processing, and data inconsistency if not handled with care. You'll leave with real-world war stories, practical advice, and concrete examples of what not to do'plus tips to build resilient, predictable serverless systems. Even seasoned AWS developers will likely discover a few surprises.
