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Quickstart

This walkthrough takes you from an empty project to a FastAPI service with production instrumentation — metrics, health checks, CORS, Swagger, and structured logging — wired up in a few lines. The same pattern applies to Litestar, FastStream, FastMCP, and framework-free services.

1. Install

Install lite-bootstrap with the FastAPI extras. fastapi-all pulls in every supported instrument:

uv add lite-bootstrap[fastapi-all]

pip install lite-bootstrap[fastapi-all]

poetry add lite-bootstrap[fastapi-all]

Want only some instruments? See the extras matrix in Installation.

2. Bootstrap your application

Create main.py:

from fastapi import FastAPI
from lite_bootstrap import FastAPIConfig, FastAPIBootstrapper

config = FastAPIConfig(
    service_name="my-service",
    service_version="1.0.0",
    service_environment="local",
    prometheus_metrics_path="/metrics",
    health_checks_enabled=True,
    health_checks_path="/health",
    cors_allowed_origins=["*"],
    swagger_offline_docs=True,
)

app: FastAPI = FastAPIBootstrapper(config).bootstrap()


@app.get("/")
async def root() -> dict[str, str]:
    return {"hello": "world"}

bootstrap() returns a ready FastAPI app with every configured instrument attached.

3. Run it

uvicorn main:app --reload

4. What you get

With the config above, your service now exposes:

  • Metrics at /metrics in Prometheus format — point your scraper at it.
  • Health check at /health — wire it to your orchestrator's readiness probe.
  • Swagger UI at /docs — with offline assets, so it renders without a CDN.
  • CORS headers for the configured origins.
  • Structured logging via structlog — enabled by default (opt out with logging_enabled=False).

5. Enable more

Each instrument is opt-in: add its config field to turn it on. Unset (or empty) fields are skipped automatically, so you only pay for what you enable.

config = FastAPIConfig(
    service_name="my-service",
    service_version="1.0.0",
    service_environment="local",
    # tracing — spans exported to your OTLP endpoint
    opentelemetry_endpoint="http://localhost:4317",
    # error reporting
    sentry_dsn="https://examplePublicKey@o0.ingest.sentry.io/0",
    # continuous profiling (needs the `pyroscope` extra)
    pyroscope_endpoint="http://localhost:4040",
)

To see exactly which instruments were enabled or skipped at startup, inspect the bootstrapper:

bootstrapper = FastAPIBootstrapper(config)
app = bootstrapper.bootstrap()

print(bootstrapper.build_summary())          # human-readable summary
for cls, reason in bootstrapper.skipped_instruments:
    print(f"skipped {cls.__name__}: {reason}")

Next steps

  • Configuration — every config field and per-instrument option.
  • Integrations — Litestar, FastStream, FastMCP, and framework-free services.