The startup database default is PostgreSQL, and for good reason: it's battle-tested, widely hosted (Supabase, Neon, Railway all offer managed PostgreSQL), has excellent tooling, and scales to significant production load. But the modern SQLite ecosystem has matured to the point where it's worth serious evaluation for early-stage products.
PostgreSQL is the right call when: you need multiple application servers writing concurrently (SQLite's single-writer lock is a hard constraint), you expect write traffic above ~1,000 writes/second from the start, your team already has PostgreSQL experience, or you're building multi-tenant SaaS where row-level security and user isolation are required from day one. Neon (serverless PostgreSQL, free tier, instant branching) is the best managed PostgreSQL for startups in 2026 — scale to zero, branch the database for each pull request, $0 for the free tier.
SQLite is the right call when: you're building a product with 1 application server, read traffic heavily dominates writes, you want zero infrastructure complexity, or you're building something that runs on-device (mobile, desktop, edge). The Litestream project adds continuous replication to S3 — your SQLite database streams WAL segments to S3 in real time, giving you sub-30-second recovery point objective at $0.023/GB/month storage cost. Turso extends SQLite across regions as a distributed database with an HTTP API — $0 for the free tier (500 databases), $29/month for production.
The case for SQLite that surprises teams: it's fast. SQLite reads are faster than PostgreSQL for single-server workloads because there's no network round trip. A localhost PostgreSQL query takes 1-5ms including network. A SQLite query is 100-500 microseconds. For applications making hundreds of queries per request, this adds up.
Practical advice: if you're building a multi-tenant SaaS with PostgreSQL row-level security planned, start with PostgreSQL (Neon free tier). If you're building a product with a single primary database server and mostly reads, give SQLite + Litestream a serious look. You'll spend zero time on database infrastructure and add it later only if you outgrow the single-writer model.