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framework · fastapi

Send email from FastAPI

Async-first. Provider SDKs without async support need an httpx wrapper or a thread pool.

FastAPI runs on uvicorn or hypercorn. Sends should be non-blocking; workers handle retries.

patterns

Send patterns

  • Async send through httpx for providers without async SDKs.
  • BackgroundTasks for fire-and-forget sends.
  • Pydantic models for outbound payload validation.
  • Webhook routes with signature verification.
pitfalls

Common mistakes

  • Calling sync SDKs in async handlers blocks the event loop.
  • BackgroundTasks for production sends drops on crash. Use a real queue.

provider picks for FastAPI

  1. 01

    Postmark

    Transactional

    Stable HTTP API; easy to wrap in httpx.

    100/mo developer plan · $15/mo for 10,000 emails
  2. 02

    Amazon SES

    Transactional

    aiobotocore for async SES.

    3,000 message charges/mo free for first 12 months · $0.10 per 1,000 emails
  3. 03

    Mailgun

    Transactional

    HTTP API and async-friendly via httpx.

    100/day on Foundation trial · $15/mo for 10,000 emails (Basic)
Want a language-level SDK comparison instead? See the SDK hub.