curl --request POST \
  --url https://{instance}.domo.com/instances/message \
  --header 'Content-Type: application/json' \
  --header 'X-DOMO-Developer-Token: <api-key>' \
  --data '
{
  "messageName": "Start MyWorkflow",
  "version": "0.0.1",
  "modelId": "a8afdc89-9491-4ee4-b7c3-b9e9b86c0138",
  "data": {
    "parameter1": 13,
    "parameter2": 7
  }
}
'

import requests

url = "https://{instance}.domo.com/instances/message"

payload = {
    "messageName": "Start MyWorkflow",
    "version": "0.0.1",
    "modelId": "a8afdc89-9491-4ee4-b7c3-b9e9b86c0138",
    "data": {
        "parameter1": 13,
        "parameter2": 7
    }
}
headers = {
    "X-DOMO-Developer-Token": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'X-DOMO-Developer-Token': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    messageName: 'Start MyWorkflow',
    version: '0.0.1',
    modelId: 'a8afdc89-9491-4ee4-b7c3-b9e9b86c0138',
    data: {parameter1: 13, parameter2: 7}
  })
};

fetch('https://{instance}.domo.com/instances/message', 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://{instance}.domo.com/instances/message",
  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([
    'messageName' => 'Start MyWorkflow',
    'version' => '0.0.1',
    'modelId' => 'a8afdc89-9491-4ee4-b7c3-b9e9b86c0138',
    'data' => [
        'parameter1' => 13,
        'parameter2' => 7
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "X-DOMO-Developer-Token: <api-key>"
  ],
]);

$response = curl_exec($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://{instance}.domo.com/instances/message"

	payload := strings.NewReader("{\n  \"messageName\": \"Start MyWorkflow\",\n  \"version\": \"0.0.1\",\n  \"modelId\": \"a8afdc89-9491-4ee4-b7c3-b9e9b86c0138\",\n  \"data\": {\n    \"parameter1\": 13,\n    \"parameter2\": 7\n  }\n}")

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

	req.Header.Add("X-DOMO-Developer-Token", "<api-key>")
	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://{instance}.domo.com/instances/message")
  .header("X-DOMO-Developer-Token", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"messageName\": \"Start MyWorkflow\",\n  \"version\": \"0.0.1\",\n  \"modelId\": \"a8afdc89-9491-4ee4-b7c3-b9e9b86c0138\",\n  \"data\": {\n    \"parameter1\": 13,\n    \"parameter2\": 7\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://{instance}.domo.com/instances/message")

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

request = Net::HTTP::Post.new(url)
request["X-DOMO-Developer-Token"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"messageName\": \"Start MyWorkflow\",\n  \"version\": \"0.0.1\",\n  \"modelId\": \"a8afdc89-9491-4ee4-b7c3-b9e9b86c0138\",\n  \"data\": {\n    \"parameter1\": 13,\n    \"parameter2\": 7\n  }\n}"

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

{
  "id": "2052e10a-d142-4391-a731-2be1ab1c0188",
  "modelId": "a8afdc89-9491-4ee4-b7c3-b9e9b86c0138",
  "modelName": "AddTwoNumbers",
  "modelVersion": "1.1.0",
  "createdBy": "8811501",
  "createdOn": "2023-11-15T15:28:57.479Z",
  "updatedBy": "8811501",
  "updatedOn": "2023-11-15T15:28:57.479Z",
  "status": null
}