Cheatsheets for FastAPI. Pair with the FastAPI textbook for depth.
Cheatsheet: GET/POST/etc decorators, path/query/body/header/cookie/form/file params, APIRouter, prefixes, dependencies on routers, and url_path_for.
Cheatsheet: BaseModel, Field, validators, custom errors, nested, discriminated unions, strict mode at the boundary.
Cheatsheet: response_model, exclusion, custom encoders, JSON / HTML / Streaming / File responses, status codes, headers.
Cheatsheet: Depends, yield-deps, sub-deps, class deps, security deps, dependency_overrides for tests, lifespan.
Cheatsheet: argon2 hashing, OAuth2 password flow, refresh tokens, sessions, API keys, scopes, RBAC, resource-level authz.
Cheatsheet: async def vs def, AnyIO/TaskGroup, to_thread, blocking traps, semaphores, timeouts, cancellation.
Cheatsheet: WebSocket handlers, auth patterns, broadcast (single + multi-process), SSE, NDJSON, heartbeats.
Cheatsheet: BackgroundTasks for fire-and-forget, ARQ / Celery / Dramatiq enqueue patterns, idempotency.
Cheatsheet: AsyncClient + pytest-anyio, dependency overrides, testcontainers Postgres, factory_boy, OpenAPI tests.
Cheatsheet: structlog with contextvars, OTEL auto-instrumentation, custom spans, Prometheus middleware, /metrics.