FastAPI with PostgreSQL and SQLAlchemy

Move beyond basic FastAPI routes and learn how to build database-backed Python APIs that are structured for real-world development.

FastAPI makes it easy to create modern APIs-but production applications need reliable persistence, safe database operations, maintainable models, controlled schema changes, and efficient queries.

FastAPI with PostgreSQL and SQLAlchemy takes you step by step through building a practical relational database layer for FastAPI using modern Python development practices.

Instead of disconnected examples, you will build and evolve a realistic SupportDesk API, learning how customers, tickets, comments, and tags fit together inside a relational backend.

You will learn how to:

• Connect FastAPI to PostgreSQL with SQLAlchemy 2.x and Psycopg 3
• Configure database URLs and manage SQLAlchemy Engines and Sessions safely
• Design modern ORM models with Mapped, mapped_column, constraints, defaults, indexes, and timestamps
• Manage database schema changes with Alembic migrations
• Build complete Create, Read, Update, and Delete (CRUD) APIs
• Separate database operations from FastAPI route logic
• Model one-to-many and many-to-many relationships
• Work with foreign keys, association tables, cascades, and related data
• Prevent N+1 query problems with deliberate relationship loading
• Connect Pydantic schemas cleanly to SQLAlchemy ORM models
• Add filtering, sorting, and pagination to database queries
• Handle database errors, transactions, commits, and rollbacks correctly
• Improve query performance with indexes, bounded queries, and PostgreSQL execution plans
• Manage environment configuration, secrets, and connection pooling
• Test real PostgreSQL database operations
• Prepare Alembic migrations and FastAPI database infrastructure for production deployment

The book focuses on modern SQLAlchemy 2.x patterns, avoiding outdated session.query() tutorials and unnecessary architectural complexity. Each concept is introduced when it becomes useful, with practical code and clear explanations of what FastAPI, SQLAlchemy, Psycopg, Alembic, Pydantic, and PostgreSQL are each responsible for.

This book is ideal for Python developers who already understand basic FastAPI concepts and are ready to build APIs that store and manage real relational data. No advanced PostgreSQL or SQLAlchemy experience is required.

By the end, you will understand not only how to connect FastAPI to a database, but how to design a database-backed API that is maintainable, testable, transaction-safe, migration-ready, and prepared for production.

Build the database foundation your FastAPI applications need to grow beyond simple demos and into real backend systems.

Book 2 of the FastAPI Development Series.