curl --request POST \
  --url 'https://api.hubapi.com/crm/extensions/cards-dev/2026-03/{appId}?hapikey=' \
  --header 'Content-Type: application/json' \
  --data '
{
  "actions": {
    "baseUrls": [
      "<string>"
    ]
  },
  "display": {
    "properties": [
      {
        "label": "<string>",
        "name": "<string>",
        "options": [
          {
            "label": "<string>",
            "name": "<string>"
          }
        ]
      }
    ]
  },
  "fetch": {
    "objectTypes": [
      {
        "propertiesToSend": [
          "<string>"
        ]
      }
    ],
    "targetUrl": "<string>",
    "serverlessFunction": "<string>"
  },
  "title": "<string>"
}
'

import requests

url = "https://api.hubapi.com/crm/extensions/cards-dev/2026-03/{appId}?hapikey="

payload = {
    "actions": { "baseUrls": ["<string>"] },
    "display": { "properties": [
            {
                "label": "<string>",
                "name": "<string>",
                "options": [
                    {
                        "label": "<string>",
                        "name": "<string>"
                    }
                ]
            }
        ] },
    "fetch": {
        "objectTypes": [{ "propertiesToSend": ["<string>"] }],
        "targetUrl": "<string>",
        "serverlessFunction": "<string>"
    },
    "title": "<string>"
}
headers = {"Content-Type": "application/json"}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({
    actions: {baseUrls: ['<string>']},
    display: {
      properties: [
        {
          label: '<string>',
          name: '<string>',
          options: [{label: '<string>', name: '<string>'}]
        }
      ]
    },
    fetch: {
      objectTypes: [{propertiesToSend: ['<string>']}],
      targetUrl: '<string>',
      serverlessFunction: '<string>'
    },
    title: '<string>'
  })
};

fetch('https://api.hubapi.com/crm/extensions/cards-dev/2026-03/{appId}?hapikey=', 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.hubapi.com/crm/extensions/cards-dev/2026-03/{appId}?hapikey=",
  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([
    'actions' => [
        'baseUrls' => [
                '<string>'
        ]
    ],
    'display' => [
        'properties' => [
                [
                                'label' => '<string>',
                                'name' => '<string>',
                                'options' => [
                                                                [
                                                                                                                                'label' => '<string>',
                                                                                                                                'name' => '<string>'
                                                                ]
                                ]
                ]
        ]
    ],
    'fetch' => [
        'objectTypes' => [
                [
                                'propertiesToSend' => [
                                                                '<string>'
                                ]
                ]
        ],
        'targetUrl' => '<string>',
        'serverlessFunction' => '<string>'
    ],
    'title' => '<string>'
  ]),
  CURLOPT_HTTPHEADER => [
    "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.hubapi.com/crm/extensions/cards-dev/2026-03/{appId}?hapikey="

	payload := strings.NewReader("{\n  \"actions\": {\n    \"baseUrls\": [\n      \"<string>\"\n    ]\n  },\n  \"display\": {\n    \"properties\": [\n      {\n        \"label\": \"<string>\",\n        \"name\": \"<string>\",\n        \"options\": [\n          {\n            \"label\": \"<string>\",\n            \"name\": \"<string>\"\n          }\n        ]\n      }\n    ]\n  },\n  \"fetch\": {\n    \"objectTypes\": [\n      {\n        \"propertiesToSend\": [\n          \"<string>\"\n        ]\n      }\n    ],\n    \"targetUrl\": \"<string>\",\n    \"serverlessFunction\": \"<string>\"\n  },\n  \"title\": \"<string>\"\n}")

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

	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.hubapi.com/crm/extensions/cards-dev/2026-03/{appId}?hapikey=")
  .header("Content-Type", "application/json")
  .body("{\n  \"actions\": {\n    \"baseUrls\": [\n      \"<string>\"\n    ]\n  },\n  \"display\": {\n    \"properties\": [\n      {\n        \"label\": \"<string>\",\n        \"name\": \"<string>\",\n        \"options\": [\n          {\n            \"label\": \"<string>\",\n            \"name\": \"<string>\"\n          }\n        ]\n      }\n    ]\n  },\n  \"fetch\": {\n    \"objectTypes\": [\n      {\n        \"propertiesToSend\": [\n          \"<string>\"\n        ]\n      }\n    ],\n    \"targetUrl\": \"<string>\",\n    \"serverlessFunction\": \"<string>\"\n  },\n  \"title\": \"<string>\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.hubapi.com/crm/extensions/cards-dev/2026-03/{appId}?hapikey=")

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

request = Net::HTTP::Post.new(url)
request["Content-Type"] = 'application/json'
request.body = "{\n  \"actions\": {\n    \"baseUrls\": [\n      \"<string>\"\n    ]\n  },\n  \"display\": {\n    \"properties\": [\n      {\n        \"label\": \"<string>\",\n        \"name\": \"<string>\",\n        \"options\": [\n          {\n            \"label\": \"<string>\",\n            \"name\": \"<string>\"\n          }\n        ]\n      }\n    ]\n  },\n  \"fetch\": {\n    \"objectTypes\": [\n      {\n        \"propertiesToSend\": [\n          \"<string>\"\n        ]\n      }\n    ],\n    \"targetUrl\": \"<string>\",\n    \"serverlessFunction\": \"<string>\"\n  },\n  \"title\": \"<string>\"\n}"

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

{
  "actions": {
    "baseUrls": [
      "<string>"
    ]
  },
  "auditHistory": [
    {
      "actionType": "CREATE",
      "applicationId": 123,
      "authSource": "APP",
      "changedAt": 123,
      "initiatingUserId": 123,
      "objectTypeId": 123
    }
  ],
  "display": {
    "properties": [
      {
        "dataType": "BOOLEAN",
        "label": "<string>",
        "name": "<string>",
        "options": [
          {
            "label": "<string>",
            "name": "<string>",
            "type": "DANGER"
          }
        ]
      }
    ]
  },
  "fetch": {
    "objectTypes": [
      {
        "name": "companies",
        "propertiesToSend": [
          "<string>"
        ]
      }
    ],
    "targetUrl": "<string>"
  },
  "id": "<string>",
  "title": "<string>",
  "createdAt": "2023-11-07T05:31:56Z",
  "updatedAt": "2023-11-07T05:31:56Z"
}

{
  "message": "Invalid input (details will vary based on the error)",
  "correlationId": "aeb5f871-7f07-4993-9211-075dc63e7cbf",
  "category": "VALIDATION_ERROR",
  "links": {
    "knowledge-base": "https://www.hubspot.com/products/service/knowledge-base"
  }
}