Lessons from Pix: How to build a real-time payments platform at its full potential

Pix, the real-time payments rail created by the Brazilian Central Bank, has gained notoriety for its impressive numbers, including over 148 million unique users and 8 billion transactions in the last three months alone. Its systemic effects are also significant, including a 10% reduction in total cash circulation and increased financial inclusion. This paper provides a comprehensive deep dive into Pix's design and protocol, highlighting critical decisions and tradeoffs and providing recommendations for other countries building fast payment systems.