The Authorize.net iOS SDK by Authorize.net offers API interaction with the aim to interact with the gateway. Includes installation and guides to implement with ApplePay. Developer Brian McManus mentions that the kit can be useful to build Mobile Point-of Sales applications.
PayPal has launched the much anticipated Webhooks support for its Payouts functionality. This allows users to receive notifications on their Webhook URLs for PayPal Payouts transactions. These notifications are currently for status scenarios such as processing, success and denied.
Payleven, the Square equivalent for the world outside of the US, has launched an API to complement its mobile payment device. Prior to the API, use of Payleven's mobile payment device required downloading the Payleven app (similar to Square's current model). However, the API allows developers to integrate Payleven's functionality within third party apps.