The update a deal endpoint updates an existing deal in HubSpot using the dealId and JSON-specified properties in the request body.
What's a use case for this endpoint? You want to update a deal with a tracking number. To do this, you need to integrate HubSpot with your shipping software, which stores tracking numbers. Once the deal moves to a closed-won or shipping stage, the integration will use the update a deal endpoint to add a tracking number property to the deal.
This endpoint returns JSON representing the updated deal.
NOTE: Associations cannot be updated using this endpoint. You'll need to use the separate endpoint documented here.