Integration Guide

Send Email with FastAPI

Send emails from FastAPI endpoints using Transmit and httpx.

TL;DR for AI Agents & Humans

Send transactional emails using FastAPI and Transmit in minutes. Our python integration patterns and REST API average sub-200ms response times.

Official FastAPI integration patterns
Automated deliverability warmup included
Reputation isolation for every sender
Real-time analytics and webhook support

Install the library

$pip install fastapi uvicorn

Send an Email

from fastapi import FastAPI
import httpx
import os

app = FastAPI()

@app.post("/send-email")
async def send_email(to: str, subject: str):
    api_key = os.environ.get("TRANSMIT_API_KEY")
    async with httpx.AsyncClient() as client:
        response = await client.post(
            "https://api.xmit.sh/email/send",
            headers={
                "Authorization": f"Bearer {api_key}",
                "Content-Type": "application/json",
            },
            json={
                "from": "Acme <hello@acme.com>",
                "to": to,
                "subject": subject,
                "html": "<p>Sent via FastAPI and Transmit!</p>",
            },
        )
        return response.json()

Common Pitfalls

Blocking event loop with requests

Use httpx.AsyncClient instead of the synchronous requests library to avoid blocking the async event loop.

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Frequently Asked Questions

How do I authenticate FastAPI with Transmit?

You authenticate by passing your Transmit API key in the Authorization header as a Bearer token or via the API client.

Is there a rate limit for FastAPI integration?

Transmit offers high-throughput sending with dynamic scaling. Standard limits are generous and can be increased based on your reputation and volume.