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Python / Uvicorn Fundamentals Interview Questions

What are the key Uvicorn settings for a production-hardened deployment?

Development defaults are convenient but inappropriate for production. A hardened production configuration disables debug features, removes identifying headers, tunes performance, and restricts network exposure.

# Production-hardened Uvicorn command
uvicorn main:app \
    --host 0.0.0.0 \
    --port 8000 \
    --workers 4 \
    --loop uvloop \
    --http httptools \
    --log-level warning \
    --no-access-log \
    --no-server-header \
    --no-date-header \
    --proxy-headers \
    --forwarded-allow-ips "10.0.0.0/8"

# Or using environment variables (recommended for containers):
export UVICORN_HOST=0.0.0.0
export UVICORN_PORT=8000
export UVICORN_WORKERS=4
export UVICORN_LOOP=uvloop
export UVICORN_HTTP=httptools
export UVICORN_LOG_LEVEL=warning
export UVICORN_NO_ACCESS_LOG=true
export UVICORN_NO_SERVER_HEADER=true
export UVICORN_PROXY_HEADERS=true
export UVICORN_FORWARDED_ALLOW_IPS="10.0.0.0/8"
uvicorn main:app

Production settings rationale
SettingReason
--no-server-headerHides 'uvicorn' from Server response header - reduces attack surface
--no-date-headerSlightly reduces response size; date often added by reverse proxy
--log-level warningEliminates per-request log I/O - reduces CPU by ~10% under load
--no-access-logSame reason; access logging often better done at proxy layer
--no-reloadNever use reload in production - it single-processes and slows startup
--loop uvloop2-4x event loop throughput improvement
--http httptoolsFaster HTTP parsing than h11

For maximum reliability in production, pair with Gunicorn (pip install uvicorn-worker) for process supervision, and a reverse proxy (Nginx, Caddy) for SSL termination and rate limiting.

What does --no-server-header do in a production Uvicorn deployment?
Why should --reload never be used in a production Uvicorn deployment?

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