curl --request POST \
  --url http://{host}:{port}/{contextPath}/migration/generate \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "sourceProcessDefinitionId": "aProcessDefinitionId1",
  "targetProcessDefinitionId": "aProcessDefinitionId2",
  "updateEventTriggers": true,
  "variables": {
    "foo": {
      "type": "Object",
      "value": "[5,6]",
      "valueInfo": {
        "objectTypeName": "java.util.ArrayList",
        "serializationDataFormat": "application/json"
      }
    }
  }
}
'

import requests

url = "http://{host}:{port}/{contextPath}/migration/generate"

payload = {
    "sourceProcessDefinitionId": "aProcessDefinitionId1",
    "targetProcessDefinitionId": "aProcessDefinitionId2",
    "updateEventTriggers": True,
    "variables": { "foo": {
            "type": "Object",
            "value": "[5,6]",
            "valueInfo": {
                "objectTypeName": "java.util.ArrayList",
                "serializationDataFormat": "application/json"
            }
        } }
}
headers = {
    "Authorization": "Basic <encoded-value>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Basic <encoded-value>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    sourceProcessDefinitionId: 'aProcessDefinitionId1',
    targetProcessDefinitionId: 'aProcessDefinitionId2',
    updateEventTriggers: true,
    variables: {
      foo: {
        type: 'Object',
        value: '[5,6]',
        valueInfo: {
          objectTypeName: 'java.util.ArrayList',
          serializationDataFormat: 'application/json'
        }
      }
    }
  })
};

fetch('http://{host}:{port}/{contextPath}/migration/generate', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_PORT => "62437",
  CURLOPT_URL => "http://{host}:{port}/{contextPath}/migration/generate",
  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([
    'sourceProcessDefinitionId' => 'aProcessDefinitionId1',
    'targetProcessDefinitionId' => 'aProcessDefinitionId2',
    'updateEventTriggers' => true,
    'variables' => [
        'foo' => [
                'type' => 'Object',
                'value' => '[5,6]',
                'valueInfo' => [
                                'objectTypeName' => 'java.util.ArrayList',
                                'serializationDataFormat' => 'application/json'
                ]
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Basic <encoded-value>",
    "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 := "http://{host}:{port}/{contextPath}/migration/generate"

	payload := strings.NewReader("{\n  \"sourceProcessDefinitionId\": \"aProcessDefinitionId1\",\n  \"targetProcessDefinitionId\": \"aProcessDefinitionId2\",\n  \"updateEventTriggers\": true,\n  \"variables\": {\n    \"foo\": {\n      \"type\": \"Object\",\n      \"value\": \"[5,6]\",\n      \"valueInfo\": {\n        \"objectTypeName\": \"java.util.ArrayList\",\n        \"serializationDataFormat\": \"application/json\"\n      }\n    }\n  }\n}")

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

	req.Header.Add("Authorization", "Basic <encoded-value>")
	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("http://{host}:{port}/{contextPath}/migration/generate")
  .header("Authorization", "Basic <encoded-value>")
  .header("Content-Type", "application/json")
  .body("{\n  \"sourceProcessDefinitionId\": \"aProcessDefinitionId1\",\n  \"targetProcessDefinitionId\": \"aProcessDefinitionId2\",\n  \"updateEventTriggers\": true,\n  \"variables\": {\n    \"foo\": {\n      \"type\": \"Object\",\n      \"value\": \"[5,6]\",\n      \"valueInfo\": {\n        \"objectTypeName\": \"java.util.ArrayList\",\n        \"serializationDataFormat\": \"application/json\"\n      }\n    }\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("http://{host}:{port}/{contextPath}/migration/generate")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Basic <encoded-value>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"sourceProcessDefinitionId\": \"aProcessDefinitionId1\",\n  \"targetProcessDefinitionId\": \"aProcessDefinitionId2\",\n  \"updateEventTriggers\": true,\n  \"variables\": {\n    \"foo\": {\n      \"type\": \"Object\",\n      \"value\": \"[5,6]\",\n      \"valueInfo\": {\n        \"objectTypeName\": \"java.util.ArrayList\",\n        \"serializationDataFormat\": \"application/json\"\n      }\n    }\n  }\n}"

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

{
  "sourceProcessDefinitionId": "aProcessDefinitionId1",
  "targetProcessDefinitionId": "aProcessDefinitionId2",
  "instructions": [
    {
      "sourceActivityIds": [
        "aUserTask"
      ],
      "targetActivityIds": [
        "aUserTask"
      ],
      "updateEventTrigger": false
    },
    {
      "sourceActivityIds": [
        "anEvent"
      ],
      "targetActivityIds": [
        "anotherEvent"
      ],
      "updateEventTrigger": true
    }
  ],
  "variables": {
    "foo": {
      "type": "Object",
      "value": "[5,6]",
      "valueInfo": {
        "objectTypeName": "java.util.ArrayList",
        "serializationDataFormat": "application/json"
      }
    }
  }
}

{
  "type": "<string>",
  "message": "<string>",
  "code": 123
}