Postgres has won the mindshare war over the last decade. MySQL still has a place — and pretending it doesn't leads to migration projects that didn't need to happen. The honest comparison in 2026 helps you know when each is the right call.
Postgres advantages
Richer SQL (window functions, CTEs, advanced types). Extension ecosystem (pgvector, PostGIS, TimescaleDB). Strong default for new projects. Better JSON handling (JSONB). The default-right answer for most new builds.
MySQL advantages
Easier replication topologies historically (though Postgres has caught up). Mature sharding ecosystem (Vitess, planetary-scale at YouTube). InnoDB clustered indexes win on point-lookup workloads. Less surprising operational behavior at very high write volume.
Vitess as a tilt factor
Vitess (open-source sharded MySQL) runs YouTube and PlanetScale. No comparable open-source sharded Postgres. If you know you'll need horizontal write scale, MySQL+Vitess is the proven path.
Ecosystem in 2026
Postgres: pgvector, TimescaleDB, Citus, Crunchy, Neon, Supabase — rich. MySQL: PlanetScale, Aurora, Vitess — also rich, narrower. Hosted offerings are roughly equivalent. Tooling for both is mature.
Choosing
Default new project: Postgres. Existing MySQL with no problems: keep MySQL. Planning for billion-row sharded writes: MySQL+Vitess. Need a Postgres extension (pgvector, PostGIS): Postgres. Most teams pick Postgres and don't regret it.