Software Developer in São Paulo - State of São Paulo, Brazil

I maintained the Django codebase for Brazil's payment system during the migration phase to the new global solution (Ruby on Rails) that was maintained by another team.

In the migration phase, I rewrote the "Boleto" payment option for Brazilian customers in the new system, handled the integration with a third-party payment services provider through webhooks, and increased test coverage with unit tests.

I also customized the React front end—enabling a seamless user experience by allowing the customer to make payments with a Boleto barcode quickly.

I paved the way for another payment option with a different payment service provider for low-credit customers, similar to a subscription model (installments).

I met with the partner company's director of engineering to agree on a custom-made solution and the design and integration.

While maintaining and refactoring a legacy codebase, I created the data visualization functionality for the company's then-main product.

I used Ruby on Rails and optimized SQL queries to aggregate preprocessed public records of São Paulo students' data and displayed that in different levels of granularity using line plots, histograms, and pie charts with React. Every school period, a background task was executed, and it updated the records.

The customer (teachers and other education professionals) could then compare different schools on a higher level or see the areas in which a particular class and/or student was struggling and act accordingly.

I rewrote a Python service using Go to improve throughput and handle the increasing load. The service fans out Sendgrid webhook calls to two other email campaign management vendors.

This project involved coordination with the email marketing analysts and also the vendor's engineering team, as that integration wasn't documented.

I created the Go service from scratch—changing the internal design to be asynchronous using Goroutines with exponential backoff for failed requests.

The result was a service that could handle webhook callbacks from email blasts to the entire user base (around ten million at the time). During peak hours, it was scaled to >10 instances, each running about 900 Goroutines concurrently.

This service enabled the email marketing team to analyze their email campaigns in real-time with confidence that their data was, in fact, correct.

I rebuilt the entire file upload feature (both frontend as well as backend).

The entire UI was rewritten from scratch using React, and I also added the ability to create nested folders.

I also wrote a drag-n-drop functionality on the desktop, including multiple file dragging.

Added a new progress bar component with the status of multiple files being uploaded in sequence.