Schema migrations with Flyway on a codebase carrying over a thousand of them, type-safe queries with jOOQ generated from the live schema, PostGIS for coordinates and distance filtering, and PL/pgSQL where it belongs. A recurring category is operational data tooling: bulk loaders, reference-data imports, time-zone and coordinate cleanup, and reporting views for an analytics layer. Per-branch database copies on Neon make testing a migration against real data routine.