Envía cartas certificadas desde tu software

curl https://api.sendregistered.com/v1/letters \
  -H "Authorization: Bearer sr_test_4f2a9Kd7Lq" \
  -H "Idempotency-Key: claim-2026-4471" \
  -H "Content-Type: application/json" \
  -d '{
    "document": "doc_8Kq2mZ",
    "product": "de-einwurf",
    "recipient": {
      "name": "Hausverwaltung Berger GmbH",
      "street": "Kastanienallee 12",
      "postal_code": "10435",
      "city": "Berlin",
      "country": "DE"
    },
    "pay": true
  }'

const res = await fetch("https://api.sendregistered.com/v1/letters", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.SR_KEY}`,
    "Idempotency-Key": "claim-2026-4471",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    document: "doc_8Kq2mZ",
    product: "de-einwurf",
    recipient: {
      name: "Hausverwaltung Berger GmbH",
      street: "Kastanienallee 12",
      postal_code: "10435",
      city: "Berlin",
      country: "DE",
    },
    pay: true,
  }),
});
const letter = await res.json();

import os, requests

letter = requests.post(
    "https://api.sendregistered.com/v1/letters",
    headers={
        "Authorization": f"Bearer {os.environ['SR_KEY']}",
        "Idempotency-Key": "claim-2026-4471",
    },
    json={
        "document": "doc_8Kq2mZ",
        "product": "de-einwurf",
        "recipient": {
            "name": "Hausverwaltung Berger GmbH",
            "street": "Kastanienallee 12",
            "postal_code": "10435",
            "city": "Berlin",
            "country": "DE",
        },
        "pay": True,
    },
).json()

{
  "id": "let_3VbN7c",
  "status": "paid",
  "product": "de-einwurf",
  "pages": 2,
  "price": { "excl_vat": 657, "vat": 138, "total": 795, "currency": "EUR" },
  "paid_from": "credit",
  "posting_date": "2026-11-09",
  "tracking_number": null,
  "livemode": false
}