PostgreSQL
What it is: Most advanced open-source relational database. JSONB support, full-text search, PostGIS for geo, extensions for everything.
What It Does Best
ACID compliance. Transactions work. Data integrity guaranteed. No surprises.
Flexible data types. JSON, arrays, ranges, custom types. SQL for structured + NoSQL for flexibility.
Extensions ecosystem. PostGIS for maps, TimescaleDB for time series, pgvector for AI embeddings.
Key Features
JSONB: Binary JSON with indexing, best of SQL and NoSQL
Advanced SQL: Window functions, CTEs, lateral joins, full text search
Extensions: Huge ecosystem (PostGIS, TimescaleDB, pgvector, pg_cron)
MVCC: Multi-version concurrency for high performance
Custom types: Define your own data types and operators
Pricing
Open Source: Free, PostgreSQL license (very permissive)
AWS RDS: From $15/month for small instances
Azure Database: Similar pricing, managed service
Google Cloud SQL: Managed Postgres with auto-scaling
When to Use It
✅ General-purpose database needs
✅ Complex queries and relationships
✅ Mixed structured + semi-structured data
✅ Need reliability and data integrity
✅ Default choice for new applications
When NOT to Use It
❌ Analytics on massive datasets (use data warehouses)
❌ Extreme scale reads (consider NoSQL + caching)
❌ Document-only storage (MongoDB simpler)
❌ Simple key-value needs (Redis/DynamoDB simpler)
❌ Embedded database (use SQLite)
Common Use Cases
Web applications: User accounts, content, transactions
SaaS products: Multi-tenant applications with complex data
Geospatial apps: Location-based services with PostGIS
Time-series data: With TimescaleDB extension
API backends: REST and GraphQL data stores
PostgreSQL vs Alternatives
vs MySQL: Postgres more features and standards-compliant, MySQL simpler
vs MongoDB: Postgres better for structured data, MongoDB for pure documents
vs SQL Server: Postgres free and more flexible, SQL Server better Microsoft integration
Unique Strengths
Most advanced open source RDBMS: Cutting-edge SQL features
Extension ecosystem: Solve new problems without leaving Postgres
Standards compliance: Most SQL-compliant open source database
JSONB: Best-in-class JSON support in relational database
Bottom line: Default choice for relational database. Free, powerful, and keeps getting better. If unsure what database to use, choose Postgres.