curl --request PUT \
  --url https://api.hubapi.com/forms/v2/forms/{form_guid} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "name": "<string>",
  "action": "<string>",
  "method": "<string>",
  "cssClass": "<string>",
  "redirect": "<string>",
  "submitText": "<string>",
  "followUpId": "<string>",
  "notifyRecipients": "<string>",
  "leadNurturingCampaignId": "<string>",
  "formFieldGroups": [
    {
      "fields": [
        {
          "name": "<string>",
          "label": "<string>",
          "type": "<string>",
          "fieldType": "<string>",
          "description": "<string>",
          "groupName": "<string>",
          "displayOrder": 123,
          "required": true,
          "selectedOptions": [
            "<string>"
          ],
          "options": [
            {}
          ],
          "validation": {
            "name": "<string>",
            "message": "<string>",
            "data": "<string>",
            "useDefaultBlockList": true,
            "blockedEmailAddresses": [
              "<string>"
            ]
          },
          "enabled": true,
          "hidden": true,
          "defaultValue": "<string>",
          "isSmartField": true,
          "unselectedLabel": "<string>",
          "placeholder": "<string>"
        }
      ],
      "default": true,
      "isSmartGroup": true
    }
  ],
  "selectedExternalOptions": [
    {
      "referenceType": "<string>",
      "objectTypeId": "<string>",
      "propertyName": "<string>",
      "id": "<string>"
    }
  ]
}'

{
  "portalId": 123,
  "guid": "<string>",
  "name": "<string>",
  "action": "<string>",
  "method": "<string>",
  "cssClass": "<string>",
  "redirect": "<string>",
  "submitText": "<string>",
  "followUpId": "<string>",
  "notifyRecipients": "<string>",
  "leadNurturingCampaignId": "<string>",
  "formFieldGroups": [
    {
      "fields": [
        {
          "name": "<string>",
          "label": "<string>",
          "type": "<string>",
          "fieldType": "<string>",
          "description": "<string>",
          "groupName": "<string>",
          "displayOrder": 123,
          "required": true,
          "selectedOptions": [
            "<string>"
          ],
          "options": [
            {}
          ],
          "validation": {
            "name": "<string>",
            "message": "<string>",
            "data": "<string>",
            "useDefaultBlockList": true,
            "blockedEmailAddresses": [
              "<string>"
            ]
          },
          "enabled": true,
          "hidden": true,
          "defaultValue": "<string>",
          "isSmartField": true,
          "unselectedLabel": "<string>",
          "placeholder": "<string>",
          "dependentFieldFilters": [
            {}
          ],
          "labelHidden": true,
          "propertyObjectType": "<string>",
          "metaData": [
            {}
          ],
          "objectTypeId": "<string>"
        }
      ],
      "default": true,
      "isSmartGroup": true,
      "richText": {
        "content": "<string>",
        "type": "<string>"
      },
      "isPageBreak": true
    }
  ],
  "createdAt": 123,
  "updatedAt": 123,
  "performableHtml": "<string>",
  "migratedFrom": "<string>",
  "ignoreCurrentValues": true,
  "metaData": [
    {}
  ],
  "deletable": true,
  "inlineMessage": "<string>",
  "tmsId": "<string>",
  "captchaEnabled": true,
  "campaignGuid": "<string>",
  "cloneable": true,
  "editable": true,
  "formType": "<string>",
  "deletedAt": 123,
  "themeName": "<string>",
  "parentId": 123,
  "style": "<string>",
  "isPublished": true,
  "publishAt": 123,
  "unpublishAt": 123,
  "publishedAt": 123,
  "customUid": "<string>",
  "createMarketableContact": true,
  "editVersion": 123,
  "thankYouMessageJson": "<string>",
  "themeColor": "<string>",
  "alwaysCreateNewCompany": true,
  "internalUpdatedAt": 123,
  "businessUnitId": 123,
  "portableKey": "<string>",
  "paymentSessionTemplateIds": [
    "<string>"
  ],
  "selectedExternalOptions": [
    {
      "referenceType": "<string>",
      "objectTypeId": "<string>",
      "propertyName": "<string>",
      "id": "<string>"
    }
  ],
  "embedVersion": "<string>"
}