Postgres
The world's most advanced open-source relational DB
MySQL
Ubiquitous open-source relational DB
Both are mature open-source relational databases. Postgres has richer SQL (CTEs, window functions, JSON, arrays, extensions), stricter standards compliance, and better for complex analytics. MySQL is simpler, often faster on basic read-heavy workloads, and dominates WordPress/PHP ecosystems.
Pick Postgres when you need complex queries, JSON handling, GIS, or extensions like pgvector.
Pick MySQL when you run a LAMP stack, need simpler ops, or use PlanetScale/Vitess for sharding.
| Feature | 🐘Postgres | 🐬MySQL | Winner |
|---|---|---|---|
| SQL standard compliance | High | Moderate | A |
| JSON support | JSONB with indexing | JSON (less mature) | A |
| Extensions | pgvector, PostGIS, TimescaleDB | Limited | A |
| Replication | Logical + streaming | Binlog, row-based | Tie |
| Read performance (simple) | Good | Often faster | B |
| Write performance (heavy) | Excellent | Good | A |
| Horizontal scaling | Citus / Spanner-compat | Vitess (PlanetScale) | B |
| Ecosystem | Rich for analytics/AI | Rich for web/CMS | Tie |
SQL standard compliance
APostgres
High
MySQL
Moderate
JSON support
APostgres
JSONB with indexing
MySQL
JSON (less mature)
Extensions
APostgres
pgvector, PostGIS, TimescaleDB
MySQL
Limited
Replication
TiePostgres
Logical + streaming
MySQL
Binlog, row-based
Read performance (simple)
BPostgres
Good
MySQL
Often faster
Write performance (heavy)
APostgres
Excellent
MySQL
Good
Horizontal scaling
BPostgres
Citus / Spanner-compat
MySQL
Vitess (PlanetScale)
Ecosystem
TiePostgres
Rich for analytics/AI
MySQL
Rich for web/CMS
Best for
Best for
Use pgloader for MySQL→Postgres — it handles schema, data, and most type mappings (watch TINYINT(1) → BOOLEAN). Postgres→MySQL is harder: no arrays, no CHECK constraints historically, different sequence semantics. Rewrite queries that use RETURNING, ILIKE, or schema-qualified names.
Both are mature open-source relational databases. Postgres has richer SQL (CTEs, window functions, JSON, arrays, extensions), stricter standards compliance, and better for complex analytics. MySQL is simpler, often faster on basic read-heavy workloads, and dominates WordPress/PHP ecosystems. In short: Postgres — The world's most advanced open-source relational DB. MySQL — Ubiquitous open-source relational DB.
Pick Postgres when you need complex queries, JSON handling, GIS, or extensions like pgvector.
Pick MySQL when you run a LAMP stack, need simpler ops, or use PlanetScale/Vitess for sharding.
Use pgloader for MySQL→Postgres — it handles schema, data, and most type mappings (watch TINYINT(1) → BOOLEAN). Postgres→MySQL is harder: no arrays, no CHECK constraints historically, different sequence semantics. Rewrite queries that use RETURNING, ILIKE, or schema-qualified names.
Yes. Both have MCP servers installable via MCPizy (mcpizy install postgres and mcpizy install mysql). They work identically across Claude Code, Claude Desktop, Cursor, Windsurf, and any other MCP-compatible client. You can install both side by side and route queries in your agent's prompt.
Supabase is managed Postgres plus auth, storage, edge functions, and realtime. Plain Postgres gives you the same battle-tested engine without the batteries — you run it yourself. Supabase wins for speed-to-product; Postgres wins for full control and cost at scale.
Both are BaaS offerings. Supabase is Postgres-based (relational, SQL, open-source), Firebase is Firestore-based (NoSQL, proprietary, Google Cloud). Supabase wins if you want SQL, lower lock-in, and predictable pricing. Firebase wins for mobile-first apps tied to Google's ecosystem.
MongoDB is a document database — flexible schemas, built-in sharding, great for unstructured data and rapid prototyping. Postgres is relational but its JSONB type covers most 'flexible schema' use-cases while also giving you joins, transactions, and stricter integrity.
Not sure? Run both side by side — swap between them in your AI agent with a single config line.