Navigating Recurring Payments in India: A Backend Perspective - Shopify

This post details the backend implementation for adapting Shopify's billing platform to new RBI regulations for recurring payments in India. Key contributions include: modeling the e-mandate concept by associating it with the 'source' object and its 'remote_reference', handling both recurring and one-time payments by tokenizing once for recurring payments to avoid user friction, implementing card payments through a PCI compliant server with AFA, and implementing UPI payments leveraging UPI AutoPay and handling its complex transaction limit logic by setting a maximum e-mandate limit of ₹5,000 and treating larger payments as one-time manual payments. It also details the backend logic for handling different payment scenarios for both cards and UPI, including sequence diagrams and entity-relationship diagrams.