The database is one of the few early decisions that is genuinely hard to reverse, so it deserves a few minutes of real thought — and then a boring, safe choice.
Default to Postgres
For most MVPs, a single Postgres instance covers relational data, JSON columns, full-text search, and queues well enough to reach product-market fit. One dependency, well understood.
When to reach for something else
SQLite is perfect for local-first or read-heavy tools. A managed document store earns its place only when your data is genuinely schemaless and huge. Both are the exception, not the default.
Optimise for the ability to change your mind, not for a scale you do not have yet.
