Uploaded December 2022 | Updated September 2026, 2 weeks ago

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Bettermarks is an adaptive learning system for mathematics.

In 2014 we decided to rewrite our backend from scratch based on EventSourcing and CQRS.

This presentation will give an overview on why we chose ES/CQRS in the first place, how we approached it and what we learned.

In these 8 years we encountered a 6-week phase of incidents with our EventStore being unreliable, we had to scale up on short notice during a free-usage-phase in the pandemic, we migrated our EventStore from MongoDB to DynamoDB, we regularly perform so-called Change-Of-Schoolyear manoevers where we actually do drop some 700 million events,…

So lots of story-telling and sharing