Piriod API is REST-based with predictable URLs resources-oriented. Accepts Form-data and JSON-encoded request bodies, returns ever JSON-encoded responses and uses standard HTTP response codes.
The Piriod API currently has a single version and has periodic changes in functionality that do not affect the attributes of the different objects that make up the API resources. This documentation explains the use of the different resources and the only source of truth.
You can use the Piriod API in test mode and thus not affect the actual data of the account. The API key is for test mode or real mode.