📍 Londrina, PR · Brazil
✉️ fernandeslucas451@gmail.com ☎️ +55 43 99944-0525
🔗 https://www.linkedin.com/in/lucascassetari

I am a pragmatic engineer who delivers product-focused systems and owns the parts teams often avoid: billing, reconciliation, and operational reliability. I convert messy legacy domains into observable, testable, and maintainable services, prioritizing business impact and continuous delivery.

• Design and delivery of backend platforms with DDD, microservices, and event-driven patterns.
• Operational engineering: idempotency, resilient retries, incident reduction and observability.
• Payments and finance flows: integrations, automated reconciliation and fiscal closing support.
• End-to-end collaboration with frontend teams (Angular, React) to ship complete features.
• Mentorship and developer experience to raise team quality without blocking delivery.

Led a full refactor of the billing domain: consolidated invoice models, improved idempotency and retries, and significantly reduced operational incidents.

Automated reconciliation and installment creation to streamline fiscal close and reduce manual interventions.

Delivered employee-transfer flows between legal entities with correct payroll allocation and accounting treatment.

Built a product that enables business teams to configure customer notifications and run NPS cycles without engineering involvement.

Integrated multiple payment gateways and automated billing and operations reports.

C# · .NET Core · ASP.NET · TypeScript · Angular · React
AWS (Lambda, ECS, EKS, EC2) · Docker · Kubernetes · Kafka · RabbitMQ
Postgres · MongoDB · Redis · DDD · TDD · CI/CD · Observability (Datadog, Grafana, Elastic)

• Billing refactor — Férias&Co: clarified domain boundaries, added resilient retries and improved observability.
• Reconciliation & installments — Férias&Co: automated critical fiscal flows for reliable closing.
• Communications Hub — Localiza&Co: productized messaging and NPS capture for business teams.
• E-commerce & payments — Retornar: unified catalogs and automated back-office workflows.

I focus on measurable outcomes: break problems into safe increments, validate assumptions with data, and automate repeatable processes. I partner closely with product and design to turn ambiguity into clear, testable work. I mentor teammates to improve systems while keeping delivery pace.

Senior or Lead roles (remote-friendly) where I can own critical domains such as billing and integrations, and influence architecture with a clear focus on product impact.

Contact
Email is best: fernandeslucas451@gmail.com — I usually reply quickly.