João Barbosa
software engineer · goiânia, br
Building things that scale. Currently refactoring critical systems and shipping payment features at Payevo. Check out my blog to see what I'm thinking about.
I'm a FullStack Software Engineer at Payevo, a payment gateway evolving into a fintech, where I refactor critical systems and ship payment features with Next.js and Supabase — using AI as an engineering lever, with the architectural decisions always mine. My path bridges development and infrastructure: a high-impact residency at BRISA & UFG (backend for healthcare) and a solid foundation in IT infrastructure, which I now deepen in a personal R&D homelab. I'm pursuing my degree in Software Engineering while exploring architecture and distributed systems through personal projects.
Full Stack Software Engineer at a payment gateway transitioning into a fintech (Next.js, Supabase, TypeScript). I own the design and delivery of my tasks — critical refactoring of legacy modules, complex integrations with acquirers and checkouts, and auditing tools for transaction monitoring. I use AI code agents actively in implementation and refactoring, as a first layer of technical review, while the architectural decisions stay mine.
Backend developer in a high-impact technology residency, modernizing a maternal & child healthcare platform. I led the technical restructuring of a legacy system, introduced automated testing standards, and standardized containerized development environments that boosted team productivity and reliability. With limited access to in-person mentors, I used AI as a "virtual senior" to validate data modeling and architecture before implementing features.
Infrastructure role ensuring high availability and stability for public-management systems across on-premise and cloud (AWS) environments — proactive monitoring of critical services, incident response, and automation of update routines on Linux servers. I used LLMs to resolve infra and Linux questions quickly and to structure complex problems before taking them to technical leadership, saving the team time.
Experience in managing customer relationships and translating business needs into technical solutions. Developed communication and negotiation skills that facilitate requirements gathering and direct interface with stakeholders.
Focused on critical diagnostics and resolution of hardware and software failures. Provided a solid understanding of computer architecture and the physical processing layer — fundamental skills for writing performant code.
Personal containerized infrastructure used as an R&D environment for platform and DevOps practices — observability, automated updates, and zero-trust service exposure without open ports. Currently being rebuilt on Proxmox VE to enforce a real platform-vs-workload separation.
An event-sourced vertical slice of an FX remittance pipeline (BRL → USD over crypto rails), built as a take-home: a single FxOperation aggregate moves through six asynchronous steps — quote, deposit, compliance, conversion, settlement, reconcile — each emitting an immutable fact. Money is always integer cents, webhooks are idempotent at the aggregate, and the ledger is a double-entry projection proven by a Pest suite of business scenarios.
A recipe API built with FastAPI: search recipes by the ingredients you have, and when nothing matches, one is generated by AI and persisted automatically. Layered architecture with JWT auth, an isolated test suite, and the AI integration behind a single testable seam — written spec-first, then implemented with AI assistance.
A real-time multi-user chat over TLS 1.3 TCP sockets, with a custom binary-header + JSON protocol. A Java multi-module client/server where the server runs one thread per client and broadcasts to everyone connected.
A learning project on asynchronous money transfers: a Lumen/PHP API that accepts a transfer (202/pending) for a queue-based worker to settle later, with money handled in integer cents, a PHPUnit test suite, and RabbitMQ in the stack.
A fullstack technical challenge: bulk-register clients from a CSV upload and distribute them across operators, with CSV import/export. A NestJS API with unit tests per layer (services, controllers, validators) behind a Next.js frontend — TypeScript end to end.
A fullstack technical challenge to manage clients and their credit cards through a structured REST API and a relational data model. Focused on type safety, schema validation, and modern frontend practices.
Participation in Brazil's leading mobile innovation program, promoted by Instituto Claro. Development of technology solutions with social impact, collaborating with multidisciplinary teams in a high technical and creative-demand environment.
Active member of Breaking Tech, an academic group with professional-level output under faculty supervision. The group develops real software projects, integrating academic knowledge with market practices — prototyping, code review, and professional-quality deliverables.
Participated as a partner community representative at Campus Party Goiás, one of the world's largest technology and innovation festivals. Networking with industry leaders and immersion in trends across technology, entrepreneurship, and digital culture.
Let's talk.
Reach me at joao1barbosa@hotmail.com or via the social links below. Always open to interesting projects and conversations. You can also browse my blog and notebook.