Python

O SpacePost é uma API JSON simples, então qualquer cliente HTTP funciona. Não há um pacote oficial para Python; use a especificação OpenAPI para gerar um.

requests

pip install requests

send.py

import os
import requests

API = "https://api.spacepost.dev"
HEADERS = {"Authorization": f"Bearer {os.environ['SPACEPOST_API_KEY']}"}

def send_email(to: str, subject: str, html: str, idempotency_key: str | None = None) -> dict:
    headers = dict(HEADERS)
    if idempotency_key:
        headers["Idempotency-Key"] = idempotency_key
    r = requests.post(
        f"{API}/emails",
        headers=headers,
        json={"from": "Acme <hello@acme.com>", "to": [to], "subject": subject, "html": html},
        timeout=15,
    )
    body = r.json()
    if not r.ok:
        # {"statusCode": 422, "name": "validation_error", "message": "..."}
        raise RuntimeError(f"{body['name']}: {body['message']}")
    return body  # {"id": "..."}

if __name__ == "__main__":
    print(send_email("delivered@test.spacepost.dev", "Hello from Python", "<p>It works.</p>"))

httpx (assíncrono)

pip install httpx

send.py

import asyncio
import os
import httpx

async def main() -> None:
    async with httpx.AsyncClient(
        base_url="https://api.spacepost.dev",
        headers={"Authorization": f"Bearer {os.environ['SPACEPOST_API_KEY']}"},
        timeout=15,
    ) as client:
        r = await client.post(
            "/emails",
            json={
                "from": "Acme <hello@acme.com>",
                "to": ["delivered@test.spacepost.dev"],
                "subject": "Hello from httpx",
                "html": "<p>It works.</p>",
            },
        )
        r.raise_for_status()
        print(r.json())

asyncio.run(main())

Trate o 429 aguardando o tempo indicado no cabeçalho retry-after e tentando de novo com o mesmo Idempotency-Key. Veja Limites de taxa e Chaves de idempotência.

Para Django, Flask e outros frameworks, você também pode usar o relay SMTP.