PostgreSQL.
PostgreSQL is the database under almost everything Remiam ships — usually reached through Supabase, occasionally direct. The studio leans on the parts of Postgres that let logic live next to the data rather than in an application tier: row-level security for multi-tenancy, triggers for audit trails, advisory locks for anything that must never be sold twice, and PL/pgSQL functions for rules that have to hold whichever client is calling them. On the Prize Wheel kiosk that meant an allocation routine mirrored in both TypeScript and PL/pgSQL, with a per-mode advisory lock so concurrent draws serialise instead of overselling. Postgres earns its place by being boring under load and precise about correctness — two properties that matter more than feature count when an activation only gets one live run.