Lucas – Rust, PostgreSQL, Python

The company is now working on a fintech project to manage debts purchased from financial institutions incurred by rural producers.

The product itself was built to identify invoices using government and partner services, which represent debts of some producers to some financial institutions, build portfolios from those invoices, and track the profits of those portfolios.

• Led the development and maintenance of a core product responsible for analyzing debt sellers (“producers”), performing background and reputation checks, including criminal records, outstanding debts, addresses, phone numbers, emails, and owned rural properties to assess acquisition risk; • Acted as the primary technical owner of the product, ensuring reliability, scalability, and continuous evolution of the system; • Mentored and trained team members in Rust, including leading hands-on onboarding for two junior engineers who were sponsored by the company to relocate temporarily for in-person training while contributing to the project; • Collaborated closely with business stakeholders to define requirements, prioritize features, and address production issues; • Proactively monitored logs and system metrics to detect anomalies, investigate incidents, and implement corrective actions. • Built and maintained internal Rust libraries, including a custom base-63 encoder and decoder; • Experimented with distributed database solutions using Google Cloud Spanner; • Developed gRPC-based services and clients; • Used Protocol Buffers to design and prototype service interfaces; • Built and maintained event-driven RESTful services in Rust using the Axum framework, following hexagonal architecture principles; • Wrote Terraform and Terragrunt scripts to provision and manage infrastructure on Google Cloud Platform; • Optimized complex queries for PostgreSQL databases; • Created Python migration scripts interacting with multiple microservices; • Maintained Nix Flakes to standardize and reproduce development environments; • Managed Bazel build system infrastructure for frontend projects; • Implemented HTTP clients to integrate with multiple external data providers, parsing and transforming data for internal analysis and calculations.

This project belongs to a large‑scale food delivery platform in Brazil that connects customers, restaurants, and couriers in real time.

The logistics team redesigned the delivery time estimation pipeline by rewriting a core ETA service from Java to Rust and maintaining Kubernetes‑based infrastructure to keep these services reliable under high load.​ They also built a backend service to manage delivery order cancellations and automate accurate courier payouts for completed or partially completed trips.

• Joined a Rust expert team to define and promote new architectural standards as a default approach across the company; • Contributed to the rewrite of a legacy ETA calculator service (originally written in Java) into Rust; • Created new services to deal with delivery order cancellation, it reacts to SQS and Kafka queues, store cancellation data in DynamoDB, and send a "cancelled" message to a Kafka queue; • Maintained and extended legacy services while ensuring high availability in production environments; • Acted frequently as an escalation point and on-call engineer, troubleshooting production incidents; • Delivered a runtime feature-toggle to the company’s internal Kafka crate; • Designed and developed the open-source crate Avrogant for generating Avro-compatible types via Cargo build scripts and procedural macros; • Idealized and wrote an internal crate that generates liveness and readiness routes to the existing services, without doing it by hand; • Wrote a GitLab CI workflow to run the SQL migrations using Flyway and then deploy the service.

This project belongs to an agrifintech platform that helps investors safely finance grain producers by monitoring farms and crop-backed loans using satellite data and alternative data sources.

The team built an investor-facing web platform that shows what is happening on financed farms throughout the season, while an internal tool supports analysts who interpret satellite imagery and field data to validate crop status and collateral in near real time.

• Built and maintained event-driven backend services in Rust using the Actix Web framework, following hexagonal architecture best practices; • Wrote comprehensive automated tests to ensure code quality and reliable delivery; • Conducted backend and frontend code reviews to maintain engineering standards; • Developed Python scripts and Google Cloud Functions to support internal tooling and automation; • Mentored teammates and onboarded new developers in Rust and backend best practices; • Designed and maintained SQL queries and Diesel migrations for PostgreSQL databases; • Worked with geospatial data using PostGIS; • Collaborated with the frontend team to build web components using Vue, Vuex, and TypeScript; • Partnered with QA to implement and improve end-to-end (E2E) test coverage; • Wrote Terraform scripts to provision and manage Google Cloud Platform infrastructure; • Acted as technical lead within the squad, guiding backend architecture and implementation decisions. • Maintained GitHub Actions pipelines to enforce code quality standards and automate deployments; • Performed local testing of backend and frontend applications to validate functionality before release; • Contributed to system rewrites aimed at improving performance and maintainability; • Investigated and resolved production incidents, troubleshooting faulty services, and fixing critical bugs.

This project is a digital in‑car convenience platform that lets ride‑hailing drivers earn extra income by selling snacks and small everyday items to passengers through a mobile web store during trips.

Alongside the passenger‑facing store, the team also built a back‑office system that allows drivers and operations to manage inventory, track sales, and handle periodic refills of products across the fleet of vehicles.

• Contributed to the development of a monolithic REST API using Node.js and the Express framework; • Supported the mobile team in the development and maintenance of a React Native application; • Assisted the frontend team in building and improving the React web application; • Identified user needs and proposed improvements to optimize business processes; • Managed deployments across all codebases, ensuring stable and reliable releases; • Designed, improved, and maintained CI/CD pipelines to streamline delivery workflows; • Operated and maintained a Docker Swarm cluster, ensuring high availability and service reliability; • Served as a technical reference for developers, providing guidance and clarifying implementation questions; • Led technical refinement sessions, aligning implementation details and architectural decisions across the team. • Dealt with all the deployments, and to provide and receive feedback from the engineers in my team, I had to convince the CEO to actually pay those engineers, because they weren't being paid.