Both are excellent, battle-tested relational databases. For most projects, either works fine. But there are real differences.
PostgreSQL for complex queries, data integrity, JSON support, and modern features. MySQL for simple CRUD apps, WordPress, and when you need maximum read performance.
Side-by-side
| PostgreSQL | MySQL | |
|---|---|---|
| Standards compliance | Excellent | Good |
| JSON support | Excellent (JSONB) | Basic |
| Full-text search | Built-in | Built-in |
| Replication | Logical + streaming | Built-in |
| Extensions | Rich (PostGIS, pgvector) | Limited |
| Performance (reads) | Fast | Slightly faster |
| Performance (writes) | Fast | Fast |
| Complex queries | Excellent | Good |
| Default in | Supabase, Neon, Railway | WordPress, many hosting providers |
Where PostgreSQL wins
- JSONB — store and query JSON with indexes. Gives you document-database flexibility with relational guarantees.
- Advanced types — arrays, ranges, enums, custom types, full-text search vectors.
- Extensions — PostGIS for geospatial, pgvector for AI embeddings, pg_cron for scheduled jobs.
- Standards compliance — closer to the SQL standard, fewer surprises.
- CTEs and window functions — more powerful analytical queries.
Where MySQL wins
- Simpler — easier to set up and administer for basic use cases.
- WordPress — if you’re running WordPress, you need MySQL (or MariaDB).
- Read-heavy workloads — slightly faster for simple SELECT queries.
- Hosting availability — every shared hosting provider supports MySQL.
The industry trend
PostgreSQL has been gaining market share steadily. Most modern platforms default to PostgreSQL: Supabase, Neon, PlanetScale (switched from MySQL), Railway, Render. The developer ecosystem is moving toward Postgres.
How to choose
- New project? PostgreSQL. It’s more capable and the ecosystem is moving in its direction.
- WordPress? MySQL (no choice).
- Existing MySQL codebase? Stay with MySQL unless you have a specific reason to migrate.
- Need JSON storage? PostgreSQL (JSONB is excellent).
- Need geospatial? PostgreSQL (PostGIS).
- Need AI vector search? PostgreSQL (pgvector).
See also: PostgreSQL cheat sheet | SQL cheat sheet | What is PostgreSQL?