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Product Engineer with 5+ years turning ambiguous ideas into polished software, from products used by millions to AI products I own and build myself.
View selected workProduct Engineer
I'm a Product Engineer with 5+ years of experience turning ambiguous ideas into polished software, from products used by millions to AI products I own and build myself. I work across product, frontend, backend, and AI, with a particular obsession for useful interactions and software that feels finished.
Chapter 01
I learned to ship inside agencies, product teams, and large systems where quality, performance, and alignment had real consequences.
Product outcomes at scale
For a major Brazilian healthcare (Hapvida) platform used by millions, I built an in-product feedback loop that helped move its Play Store rating from 1.7 to 4.6. For one of Brazil’s largest airlines (Azul), caching and request-orchestration improvements reduced redundant API calls by 40% and load time by 30%.
Zero-to-one mobile product
At Mutant (Brazilian tech scaleup), I built the company’s first mobile app for a multi-tenant B2B communication product. Push notifications increased daily active users by 25% over three months, while a new delivery pipeline cut release cycles by 40% and sped up critical hotfixes by as much as 50%.
Platform & Design System leadership
I helped modernize a shared airline Design System used across 6+ teams, introducing modular packaging, stronger documentation, composition patterns, testing standards, and a clearer adoption path. I became a cross-project reference and mentored engineers using the system.
Applied AI in professional products
I have integrated AI into production enterprise workflows, including a private retrieval-based assistant for onboarding and business-rule discovery, and designed controlled agent workflows that connect product documentation, interface context, implementation, and browser-based verification.
Chapter 02
Products I've taken from an idea to working software, making the product, design, and engineering decisions along the way.
AI operations for automotive retailers, starting with the first customer conversation.
A place for trips to become stories, not another folder of photos.
Predictive sourcing for recruiters who need the right company signal before everyone else.
Chapter 03
The tools change quickly. These are the parts of the work I keep constant.
I like the full loop: understand the problem, choose the smallest useful scope, design the experience, build the system, ship it, and learn from real use.
A model call is not a product. Useful AI needs context, tools, product boundaries, failure handling, and an experience people can trust.
I use agents, MCP, skills, subagents, documentation, tests, browser inspection, and small reviewable slices. The goal is faster engineering without giving up judgment or control.
Clarity, interaction, performance, and polish shape whether people trust and enjoy a product. I care about those details all the way through implementation.
Chapter 04
I started learning software in 2019 through a technical program in São Vicente, Brazil. I stood out in the class, and one of my teachers referred me to my first developer role.
Chapter 05
Route A · Full-time
I'm interested in Product Engineer and AI Product Engineer roles at startup and product teams where engineers own outcomes, work across boundaries, ship quickly, and stay close to users.
Route B · Freelance
I help founders and teams turn AI prototypes and internal workflows into reliable products. Good-fit work includes private data and RAG, product integrations, agent workflows, evals and guardrails, observability, performance, and the user experience around the AI.
The best starting point is an existing problem, workflow, prototype, or user need, not a request to add AI without a product reason.
Tell me what you're building
Start a chat with Mario