Authentication Schema
Once you’ve selected an App, you can fetch the list of Authentications a user owns for that App by making a request to the /authentications endpoint: 
// GET /authentications?app=81f613aa-c98a-4383-a5fc-195e68647217
{
  "links": {
    "next": null,
    "prev": null
  },
  "meta": {
    "count": 1,
    "limit": 10,
    "offset": 0
  },
  "data": [
    {
      "type": "authentication",
      "id": "example_akLLd8kB",
      "app": "81f613aa-c98a-4383-a5fc-195e68647217",
      "is_expired": false,
      "title": "Google Sheets some.user@mycompany.example"
    }
  ]
}
This endpoint returns only owned Authentications. Shared Authentications are excluded because Zaps can only be created using credentials that belong to the current user.
You’ll typically use this endpoint after selecting an App to identify which Authentication the user should use when configuring a Zap or Action.
Working with a lot of credentials? Use the limit and offset parameters to paginate through results.
This API is rate limited.