Is there a sandbox or mock API for Gamma to avoid burning credits during development?

During the dev and testing phase of using the Gamma API, I burned through the monthly 50 credits too quickly. At this stage, I’m just experimenting and not trying to generate a real post yet. Is there a mock or sandbox API that provides a testing environment? I don’t mind if it’s just a static dummy post; I just need an endpoint to simulate real environment request and response handling while developing my applications. Or anyone has suggestions on the best practice to develop against Gamma API without burning the credits?