Brazil's Open Finance is the world's largest. 100M+ customers, 5B+ weekly API calls. But the docs for developers are dense, fragmented, and take weeks to untangle. The Open Finance Playground is an open-source set of step-by-step implementation guides with a live simulator showing every API call behind each UX flow, consent, payment initiation, data access. Built by Juspay (global payments technology company powering 300M+ transactions per day) and Cumbuca (licensed Payment Institution)