I started the quarter trying to raise test coverage on one monorepo. I finished it having also rewritten the test pipeline, the coverage gate, the deploy workflows, and most of the backend's dependency stack. None of it was on the ticket. All of it followed from the ticket.
SBT's defaults run tests sequentially in a single JVM. On an eight-core box with a big suite, seven cores stay idle the whole run. The four settings that fix it.
Notes on a Scala framework that consumes SNS/SQS change events through Lambda — the pieces that mattered: type-safe consumer base classes, controlled parallelism via grouped futures, FIFO sharding, and the entity-refresh trick that saves you from stale reads.
How we made tenant isolation a compile-time property in a Scala SaaS backend, using an implicit QueryContext that the repository layer refuses to function without.
A Doobie abstraction layer that survives schema migrations — explicit column ordering, type-safe operators, and tenant-scoped queries by default.
Notes on the Scala query DSL we built over MongoDB to stop renames from silently breaking queries at runtime.