Deal properties store specific information for deal records. The get all deal properties endpoint retrieves all default and custom deal properties from a HubSpot account, including their definitions.
What's a use case for this endpoint? Your company wants to recreate HubSpot deals in an external CRM system. You decide to use the Get All Deal Properties endpoint to retrieve all default and custom deal properties in HubSpot. The required properties can then be parsed from the response and used in your external CRM.
Looking for your deal stages? The dealstage property is controlled by the CRM Pipelines API.