curl --request POST \
  --url https://api.omni.z-api.io/v1/channels/{channelId}/messages \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "recipient": {
    "identifier": "5511999999999"
  },
  "content": {
    "type": "IMAGE",
    "attachments": [
      {
        "url": "https://ejemplo.com/imagen.jpg",
        "caption": "Pie de la imagen"
      }
    ]
  }
}
'

import requests

url = "https://api.omni.z-api.io/v1/channels/{channelId}/messages"

payload = {
    "recipient": { "identifier": "5511999999999" },
    "content": {
        "type": "IMAGE",
        "attachments": [
            {
                "url": "https://ejemplo.com/imagen.jpg",
                "caption": "Pie de la imagen"
            }
        ]
    }
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    recipient: {identifier: '5511999999999'},
    content: {
      type: 'IMAGE',
      attachments: [{url: 'https://ejemplo.com/imagen.jpg', caption: 'Pie de la imagen'}]
    }
  })
};

fetch('https://api.omni.z-api.io/v1/channels/{channelId}/messages', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.omni.z-api.io/v1/channels/{channelId}/messages",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'recipient' => [
        'identifier' => '5511999999999'
    ],
    'content' => [
        'type' => 'IMAGE',
        'attachments' => [
                [
                                'url' => 'https://ejemplo.com/imagen.jpg',
                                'caption' => 'Pie de la imagen'
                ]
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.omni.z-api.io/v1/channels/{channelId}/messages"

	payload := strings.NewReader("{\n  \"recipient\": {\n    \"identifier\": \"5511999999999\"\n  },\n  \"content\": {\n    \"type\": \"IMAGE\",\n    \"attachments\": [\n      {\n        \"url\": \"https://ejemplo.com/imagen.jpg\",\n        \"caption\": \"Pie de la imagen\"\n      }\n    ]\n  }\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.omni.z-api.io/v1/channels/{channelId}/messages")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"recipient\": {\n    \"identifier\": \"5511999999999\"\n  },\n  \"content\": {\n    \"type\": \"IMAGE\",\n    \"attachments\": [\n      {\n        \"url\": \"https://ejemplo.com/imagen.jpg\",\n        \"caption\": \"Pie de la imagen\"\n      }\n    ]\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.omni.z-api.io/v1/channels/{channelId}/messages")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"recipient\": {\n    \"identifier\": \"5511999999999\"\n  },\n  \"content\": {\n    \"type\": \"IMAGE\",\n    \"attachments\": [\n      {\n        \"url\": \"https://ejemplo.com/imagen.jpg\",\n        \"caption\": \"Pie de la imagen\"\n      }\n    ]\n  }\n}"

response = http.request(request)
puts response.read_body

{
  "messageId": "wamid.HBgNNTU0NDk3MDUwNzg1FQIAERgSM0"
}

{
  "error": 401,
  "message": "Unauthorized"
}