You should test your integrations and know they will behave the same on the production server as they do in the Sandbox environment.
This is where an API sandbox comes in. Fundamentally, an API sandbox is an environment that testers can use to mimic the characteristics of the production environment and create simulated responses from all APIs the application relies on.
The API sandbox makes it possible to:
Sandbox mode is only used to validate your request. Any requests made in sandbox mode will not generate events Transaction Activity. No Credits will be consumed.