Whether you favor good old microservices or the cutting-edge structured monolith, chances are pretty high that your system uses message queues. That means your business logic is triggered at least once per message, as messages are re-delivered until acknowledged. That forces us to consider problems like idempotency, deduplication, and transactionality. How can we deal with these challenges?

In this talk, we'll explore various options for dealing with message redelivery. We'll discuss what we don't need, zoom in on vendor-provided snake oil labeled "exactly-once" solutions, and also dive into the industry standard for consistent message procession: the Outbox pattern. By exploring multiple variants of the Outbox pattern and comparing their respective strengths and weaknesses, you'll walk away with a thorough understanding of the topic.

To conclude the talk, I'll dust off my glass sphere and share my thoughts on the future of consistent message processing.