TL;DR: Learn Python syntax, functions, modules, exceptions, typing, and tests before adding FastAPI. Then build endpoints with validation, persistence, authentication, and observability.
Python Foundations
Practice collections, functions, classes, modules, virtual environments, exceptions, file handling, and type hints. Use a formatter, linter, and test runner from the first project.
Build the API in Layers
Start with a health endpoint, then add request and response schemas, service functions, a database repository, authentication, and background work. Keep HTTP concerns separate from business rules.
Validate at the Boundary
Treat incoming JSON, query parameters, uploaded files, and environment variables as untrusted. Validate them at the edge and return predictable errors to clients.
Production Checklist
Add unit and integration tests, structured logs, rate limits, secret management, database migrations, a container image, and a deployment pipeline. These practices make the learning project portfolio-ready.