SGBr Sistemas

Payments platform

Backend of a payment institution built from scratch by two engineers, with DDD and integrations with Santander and Banco do Brasil.

Project under confidentiality: no screenshots or product name.

Context

SGBr decided to build its own digital bank. The backend was in the hands of two engineers, and I was one of them.

Problem

Build the foundation of a financial operation from scratch, with accounts, transactions and banking integrations, ready to grow without a rewrite. Along the way, Central Bank rules prevented the use of the name "bank", and the product became a payment institution.

What I did

I split the domain with my colleague using DDD, modeled the account and transaction contexts and integrated with banking partners (Santander and Banco do Brasil) and logistics partners (Correios and Melhor Envio). I used BullMQ queues for asynchronous operations, PostgreSQL for transactional data, MongoDB for non-relational data and Redis for caching.

Outcome

The platform went into production as a payment institution, with an architecture that allowed the regulatory framing to change without rewriting the core.

Stack

NestJS
TypeScript
DDD
BullMQ
PostgreSQL
MongoDB
Redis
Docker