FastAPI Best Practices FAQs

Question 1

Why does the skill insist on using Annotated?

Accepted Answer

The Annotated style keeps function signatures clean, improves compatibility with editors and linting tools, and allows for reusable dependency and parameter definitions without breaking standard Python typing.

Question 2

How does this skill improve FastAPI performance?

Accepted Answer

It promotes the use of Pydantic return types and response models, which leverage Pydantic V2's high-speed Rust serialization instead of slower, deprecated JSON response classes.

Question 3

When should I use async def versus regular def?

Accepted Answer

Use async def only for code that is natively asynchronous and uses await. For blocking logic or when in doubt, use regular def so FastAPI can safely manage the execution in a separate threadpool.

Question 4

How should I structure my API routers?

Accepted Answer

The skill recommends declaring prefixes, tags, and dependencies directly on the APIRouter instance rather than in the include_router call to keep module logic encapsulated.

Question 5

Does this skill help with database integration?

Accepted Answer

Yes, it provides patterns for using SQLModel, which is the preferred way to work with SQL databases in FastAPI as it combines the power of SQLAlchemy with Pydantic.

FastAPI Best Practices

Key Features

Use Cases

REST API Design Patterns

Qa Javascript Typescript

Bun Runtime Optimizer