curl --request POST \
  --url https://api.wsapi.chat/messages/list \
  --header 'Content-Type: application/json' \
  --header 'X-Api-Key: <api-key>' \
  --header 'X-Instance-Id: <x-instance-id>' \
  --data '
{
  "to": "1234567890@s.whatsapp.net",
  "header": "Book a table",
  "text": "Pick a time slot for your reservation.",
  "footer": "Example Bistro",
  "buttonText": "See times",
  "sections": [
    {
      "title": "Lunch",
      "rows": [
        {
          "id": "slot-1200",
          "title": "12:00",
          "description": "Terrace available"
        },
        {
          "id": "slot-1330",
          "title": "13:30"
        }
      ]
    },
    {
      "title": "Dinner",
      "rows": [
        {
          "id": "slot-1900",
          "title": "19:00"
        },
        {
          "id": "slot-2030",
          "title": "20:30",
          "description": "Indoor seating only"
        }
      ]
    }
  ]
}
'

import requests

url = "https://api.wsapi.chat/messages/list"

payload = {
    "to": "1234567890@s.whatsapp.net",
    "header": "Book a table",
    "text": "Pick a time slot for your reservation.",
    "footer": "Example Bistro",
    "buttonText": "See times",
    "sections": [
        {
            "title": "Lunch",
            "rows": [
                {
                    "id": "slot-1200",
                    "title": "12:00",
                    "description": "Terrace available"
                },
                {
                    "id": "slot-1330",
                    "title": "13:30"
                }
            ]
        },
        {
            "title": "Dinner",
            "rows": [
                {
                    "id": "slot-1900",
                    "title": "19:00"
                },
                {
                    "id": "slot-2030",
                    "title": "20:30",
                    "description": "Indoor seating only"
                }
            ]
        }
    ]
}
headers = {
    "X-Instance-Id": "<x-instance-id>",
    "X-Api-Key": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {
    'X-Instance-Id': '<x-instance-id>',
    'X-Api-Key': '<api-key>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    to: '1234567890@s.whatsapp.net',
    header: 'Book a table',
    text: 'Pick a time slot for your reservation.',
    footer: 'Example Bistro',
    buttonText: 'See times',
    sections: [
      {
        title: 'Lunch',
        rows: [
          {id: 'slot-1200', title: '12:00', description: 'Terrace available'},
          {id: 'slot-1330', title: '13:30'}
        ]
      },
      {
        title: 'Dinner',
        rows: [
          {id: 'slot-1900', title: '19:00'},
          {id: 'slot-2030', title: '20:30', description: 'Indoor seating only'}
        ]
      }
    ]
  })
};

fetch('https://api.wsapi.chat/messages/list', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

using RestSharp;


var options = new RestClientOptions("https://api.wsapi.chat/messages/list");
var client = new RestClient(options);
var request = new RestRequest("");
request.AddHeader("X-Instance-Id", "<x-instance-id>");
request.AddHeader("X-Api-Key", "<api-key>");
request.AddJsonBody("{\n  \"to\": \"1234567890@s.whatsapp.net\",\n  \"header\": \"Book a table\",\n  \"text\": \"Pick a time slot for your reservation.\",\n  \"footer\": \"Example Bistro\",\n  \"buttonText\": \"See times\",\n  \"sections\": [\n    {\n      \"title\": \"Lunch\",\n      \"rows\": [\n        {\n          \"id\": \"slot-1200\",\n          \"title\": \"12:00\",\n          \"description\": \"Terrace available\"\n        },\n        {\n          \"id\": \"slot-1330\",\n          \"title\": \"13:30\"\n        }\n      ]\n    },\n    {\n      \"title\": \"Dinner\",\n      \"rows\": [\n        {\n          \"id\": \"slot-1900\",\n          \"title\": \"19:00\"\n        },\n        {\n          \"id\": \"slot-2030\",\n          \"title\": \"20:30\",\n          \"description\": \"Indoor seating only\"\n        }\n      ]\n    }\n  ]\n}", false);
var response = await client.PostAsync(request);

Console.WriteLine("{0}", response.Content);

{
  "id": "01234567890123456"
}

{
  "status": 400,
  "detail": "invalid request body"
}

{
  "status": 401,
  "detail": "unauthorized"
}

{
  "status": 409,
  "detail": "device not paired"
}

{
  "status": 503,
  "detail": "instance not available"
}