FluxFast for FastAPI

The Python package provides FastAPI page routes, scoped versioned resources, a bounded in-memory cache, concurrent loader resolution, mutation helpers, 422 mapping, redirects, and the fluxfast/1 protocol.

python -m pip install fluxfast

from fastapi import FastAPI
from fluxfast import FluxFast, Page, resource, scope

app = FastAPI()
flux = FluxFast(app)

@flux.page("/")
async def home():
    return Page(
        "home/index",
        resources=[
            resource("news", load_news, scope=scope.public(), ttl=60),
        ],
    )

Reusable data must declare an appropriate public, user, tenant, or custom scope. See the repository protocol and caching documentation for wire and invalidation semantics.

For a Next.js consumer, install its backend and run both development processes under one supervisor:

python -m pip install -e backend
fluxfast dev backend.app.main:app

The CLI starts FastAPI on an available internal loopback port and Next on the browser-facing development port. The companion Next config uses the injected server-only address, so browser requests stay same-origin.

Application & Resource Contracts

Declare server-owned contracts with Pydantic for typed resources and general application types:

from pydantic import BaseModel
from fluxfast import FluxFast

app = FastAPI()
flux = FluxFast(app)

class Room(BaseModel):
    id: int
    number: str

class CreateRoomInput(BaseModel):
    number: str
    floor: int

ROOMS = flux.define_resource("rooms", list[Room])
CREATE_ROOM = flux.define_type(
    "CreateRoomInput",
    CreateRoomInput,
    mode="validation",
)

Export deterministic fluxfast-schema/2 developer manifests and generate frontend contracts with one command:

fluxfast types backend.app.main:app --frontend frontend

Use --check in CI to detect contract drift without writing files. See the contract documentation and type safety guide.