PostgreSQL vs MySQL vs MongoDB

Databases: relational vs document, and which one fits your actual data model.

When to Use This Comparison

Reference this when choosing databases for new projects, migrating from legacy systems, scaling beyond SQLite, or when current database feels like wrong fit. Critical when data model and query patterns are becoming clear.

Decision Context

Your ideal database depends on data model fit, query patterns, scale requirements, team expertise, and whether you're optimizing for flexibility or consistency. CRUD apps have different needs than analytics or real-time systems.

Key Tradeoffs

PostgreSQL offers powerful features and reliability but requires careful schema design. MySQL provides simplicity and speed but fewer advanced features. MongoDB enables flexible schemas but sacrifices consistency guarantees and can surprise you at scale.

What we’re judging
Features
Query capabilities, data types, and advanced functionality.
Performance
Speed for your specific read/write patterns.
Scalability
How well it handles growth in data and traffic.
Data integrity
ACID guarantees and consistency model.
Operational complexity
Setup, maintenance, backup, and monitoring burden.
Verdict
PostgreSQL is the best default for most applications requiring data integrity. MySQL wins for simple read-heavy workloads. MongoDB is appropriate for document-oriented data but often chosen for wrong reasons.