Creating a client session generates a client token: a temporary key used to initialize Universal Checkout and authenticate it against your account.
Universal Checkout automatically retrieves all the settings from the client session and the Dashboard to configure the payment methods and the checkout experience.
Note:
When creating a Client Session, please make sure to provide currencyCode, orderId, and at least one of amount or lineItems.
If any of these are not yet available, you can provide them when making the payment request.
POST /client-session does not have required fields as all fields are not always known when a client session is created.
Use PATCH /client-session to update the parameters throughout the checkout session.
Client tokens expire after 24 hours.