The Client API allows an Application to interact with a Wallet and leverages it's features by implementing a bi-directonnal JSON-RPC 2.0 server and implementing the specification of the Platform API defined here.
The Client main role is to be integrated by any Application that wants to interact with a Ledger Wallet application (we are talking about a wallet client like Live, Vault or Connect). It will communicate the Application's intents to the Server (hosted by the Wallet client) through the JSON-RPC spec of the Platform API. It will initiate a connection to a Server through a transport layer, format and forward Application requests to the Server and return responses or errors to the Application.
All Transactions and Accounts should be serialized before being broadcasted to the Server via RPC.
Similarly, the response received from the Server, formatted as RawTransaction and RawAccount should be deserialized before being returned to the user of the Client (i.e: the Application integrating said client).
The Client will forward errors returned by the Wallet application through the Server. The only function performing checks before sending the request to the Server is completeExchange. Indeed, this function should return an error if the requested operation is a Swap but no destination account is provided.