curl --request POST \
  --url https://api.pramaan.dev/v1/capabilities/email.message.append \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'Idempotency-Key: <idempotency-key>' \
  --data '
{
  "endUserRef": "person-1",
  "app": "gmail",
  "ref": "ref_01ARZ3NDEKTSV4RRFFQ69G5FAV",
  "content": "U3ViamVjdDogSGVsbG8NCg0KSGVsbG8="
}
'

const options = {
  method: 'POST',
  headers: {
    'Idempotency-Key': '<idempotency-key>',
    Authorization: 'Bearer <token>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    endUserRef: 'person-1',
    app: 'gmail',
    ref: 'ref_01ARZ3NDEKTSV4RRFFQ69G5FAV',
    content: 'U3ViamVjdDogSGVsbG8NCg0KSGVsbG8='
  })
};

fetch('https://api.pramaan.dev/v1/capabilities/email.message.append', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

import requests

url = "https://api.pramaan.dev/v1/capabilities/email.message.append"

payload = {
    "endUserRef": "person-1",
    "app": "gmail",
    "ref": "ref_01ARZ3NDEKTSV4RRFFQ69G5FAV",
    "content": "U3ViamVjdDogSGVsbG8NCg0KSGVsbG8="
}
headers = {
    "Idempotency-Key": "<idempotency-key>",
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

{
  "status": "saved",
  "ref": "<string>"
}

{
  "error": {
    "code": "addendum_required",
    "message": "<string>",
    "next": "<string>",
    "request_id": "<string>",
    "retryable": true,
    "effect": "none",
    "slot": "<string>",
    "required_micro": 123,
    "reason": "balance",
    "top_up": {
      "message": "<string>",
      "links": [
        {
          "label": "<string>",
          "url": "<string>"
        }
      ],
      "balance_micro": 123,
      "required_micro": 123
    },
    "available_micro": 123,
    "plan": "<string>",
    "needs": [
      {
        "kind": "approval",
        "detail": "<string>",
        "step": "<string>"
      }
    ]
  }
}