The Sum Up card reader integration is compatible with iOS only (Android integration is coming soon!). However, the connection can be carried out either in your iOS App or in your Web App.
This article explains how to connect your Sum Up card reader via the iOS App
To connect your Sum Up card reader, tap the Manage tab, scroll to the Point of Sale section and tap on Card Processing:
Tap Connect in the Sum Up section, and follow the prompts to log into your Sum Up account, or create an account:
Sum Up will now appear for you as a payment method at the point of Sale, and payments made via this method will go to your Sum Up account:
Once Sum Up is selected as a payment method within a Sale, you will be prompted to pair your card reader with your iOS device (please tap the question mark in the top corner):