A partner may integrate from their servers to Zapper' on behalf of their clients. This is regarded a server to server integration and has a slightly different authentication mechanism. When a partner is on-boarded, an organisation is created within Zapper to house all of its data. Along with it a token is created. The combination of the partners' organisation id and their token is used to authenticate with Zapper and receive and identity token which can be used in subsequent requests.
A partner may choose to have their customers speak directly with Zapper's APIs. This is regarded as a client to server integration. The customer must have onboarded with Zappers APIs in order to create a customer identity. Upon creation, they will be able to login in and receive an identity token. This is similar to the server to server integration, but the token contains customer level information and access.