Python / FastAPI

Instrument FastAPI APIs.

Capture resolved route templates and customer-aware outcomes through native ASGI middleware.

FastAPI 0.100+SDK 0.2Production ready
01

Package

Install one adapter.

Python Core is installed automatically as a dependency.

Terminalbash
pip install apirelio-fastapi
02

ASGI middleware

Register Apirelio before startup.

main.pypython
import os

from fastapi import FastAPI
from apirelio_fastapi import install_apirelio

app = FastAPI()

install_apirelio(
    app,
    api_key=os.environ.get("APIRELIO_API_KEY", ""),
    endpoint=os.environ.get("APIRELIO_ENDPOINT", "https://apirelio.com"),
    service="billing-api",
    environment="production",
    include_routes=("/api/**",),
    exclude_routes=("/api/health", "/api/internal/**"),
)
03

B2B context

Resolve a stable customer.

Run authentication middleware first and expose the current account through request.state. The resolver executes after route handling.

Customer resolverpython
install_apirelio(
    app,
    # ...connection options...
    resolve_customer=lambda request: {
        "id": str(request.state.user.company_id),
        "name": request.state.user.company_name,
        "plan": request.state.user.company_plan,
    } if hasattr(request.state, "user") else None,
)
04

Lifecycle

Automatic and fail-safe.

The middleware records the final status, duration and framework route template. Events enter a bounded background queue, and FastAPI shutdown flushes pending batches. Analytics failures never replace the original response or exception.

Privacy boundary

Request and response bodies, query strings, credentials, cookies and client IP addresses are never included.