The "meta"-section is necessary for assigning the interal declaration of the entities in your CRM system to generic attributes we use in the mapping. Depending on the CRM there are various attributes which have to be provided:

Examples:

Salesforce:

"meta": {
  "lead": {
    "apiName": "Lead",
    "idProperty": "Id"
  },
  "contact": {
    "apiName": "Contact",
    "idProperty": "Id"
  },
  "account": {
    "apiName": "Account",
    "idProperty": "Id"
  },
  "campaignMember": {
    "apiName": "CampaignMember",
    "idProperty": "Id"
  },
  "task": {
    "apiName": "Task",
    "idProperty": "Id"
  }
}

Dynamics:

"meta": {
  "lead": {
    "apiName": "Lead",
    "idProperty": "LeadId",
    "logicalName": "lead"
  },
  "contact": {
    "apiName": "Contact",
    "idProperty": "ContactId",
    "logicalName": "contact"
  },
  "account": {
    "apiName": "Account",
    "idProperty": "AccountId",
    "logicalName": "account"
  },
  "appointment": {
    "apiName": "Appointment",
    "idProperty": "ActivityId",
    "logicalName": "appointment"
  },
  "task": {
    "apiName": "Task",
    "idProperty": "ActivityId",
    "logicalName": "task"
  }
}

For more details about the attributes of your CRM system please have a look at the provided mapping sample for your CRM system.

Allowed actions:

For each entity, both actions create and update can be prohibited individually.

"meta": {
  "lead": {
    "apiName": "Lead",
    "idProperty": "LeadId",
    "logicalName": "lead",
    "allowedActions": {
      "create": false,
      "update": true
    }
  }
}

Invalidations:

For each entity, the export can be blocked if certain conditions are met.

"meta": {
  "account": {
    "apiName": "account",
    "idProperty": "AccountId",
    "logicalName": "account",
    "invalidations": {
      "create": [
        {
          "message": "You are not allowed to create accounts with type supplier!",
          "condition": "{{ mergedItem.RecordTypeId == '1000001' }}"
        }
      ],
      "update": [
        {
          "message": "You are not allowed to update accounts of type customer!",
          "condition": "{{ state.contact_account.other.account.RecordTypeId == '1000001' }}"
        }
      ]
    }
  }
}