curl --request POST \
  --url https://backend.swap.coffee/v2/staking/{master_address}/positions/{address} \
  --header 'Content-Type: application/json' \
  --header 'X-Api-Key: <api-key>' \
  --header 'x-verify: <x-verify>' \
  --data '
{
  "asset_address": "EQDY6PMeMbQSz7dltNN4RRTIxyuBJX4dQESOy8cWR2tUgBxH",
  "amount_to_stake_raw": 123,
  "period_id": 123
}
'

{
  "query_id": 123,
  "message": {
    "payload_cell": "aSDinaTvuI8gbWludGxpZnk=",
    "address": "EQCM3B12QK1e4yZSf8GtBRT0aLMNyEsBc_DhVfRRtOEffLez",
    "value": "<string>",
    "state_init": "aSDinaTvuI8gbWludGxpZnk=",
    "extra": [
      {
        "id": 123,
        "amount": "<string>"
      }
    ]
  }
}