Copenhagen, Denmark 55.7°N · 12.7°E

João Oliveira

Frontend engineer — production web applications and component libraries, with hands-on backend range. Currently looking for new opportunities in Copenhagen.
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About

I'm a frontend-focused software engineer with over 6 years of experience building production interfaces and design systems, plus hands-on experience extending into distributed backend systems. Before moving into software in 2019, I worked as a firefighter/EMT and founded a craft brewery — roles that demanded composure under pressure and the coordination of complex logistics. I started my career building interfaces to train machine vision models in wastewater treatment plants, then spent three years delivering complex, production-critical web applications for major European brands — Unilabs, Fnac, the Portuguese Football Federation, and FC Porto. At Flutter/FanDuel, I owned and architected the shared component library and design system across a microfrontend sportsbook platform, led the case for accessibility and implementation consistency across backoffice tooling company-wide, and more recently broadened into distributed backend systems, building a real-time risk pipeline and microservices that process every bet placed across multiple US jurisdictions. I believe good software is testable by design and built to be changed safely — and I care about the craft beyond the code: mentoring, developer experience, and pragmatic AI adoption with measurable impact.

Currently

Our family is midway through a move from Portugal to Denmark — a new chapter we're genuinely excited about. I'm looking forward to exploring the country, its nature, and whatever surprises come with settling somewhere completely new. Lately I've also been coming back to drawing and having fun with pen and paper. Sometimes I enjoy making small circuits with a couple of buttons and LEDs so that my kids can light the nose of animals that I draw. I also love hiking and photography and am looking forward to exploring the Danish countryside with my family and teaching my kids about macro photography and how there are tiny little worlds all around us.

Craft

Frontend
React · Next.js · TypeScript · TanStack Query · CSS · web accessibility (WCAG) · Design Systems
Languages
TypeScript · Java · JavaScript
Testing
Jest · Cypress · Playwright · test-driven development · React Testing Library · automated tests · Unit Testing · JUnit
Backend
Java · Spring Boot · Node.js · Kafka
Platform
Git · Docker · CI/CD · AWS · Figma · Agile
Interests
Component Libraries · Developer Experience · Accessibility · UX · AI-Augmented Engineering

Experience

Software Engineer — Backend (Risk & Trading Insights)

09/2025 — 06/2026

Flutter Entertainment (FanDuel)

  • Broadened into backend, building distributed microservices on the real-time risk and liability pipeline behind every bet placed across multiple US jurisdictions.
  • Maintained the risk APIs behind bet placement: REST design, hexagonal architecture, and a TDD discipline across Java, Spring Boot, Kafka and Cassandra on AWS.
  • Trusted with the approach for migrating a production database from MySQL to Cassandra.

test-driven development · Java · Spring Boot · microservices · distributed systems · Kafka · MySQL · Docker · GitHub Actions · AWS · Feature flags · Hexagonal Architecture · Cassandra · Jira · Observability & Monitoring · Jenkins · SQL · Data Structures & Algorithms · Design Patterns · English (Professional Proficiency) · Documentation · SOLID Principles · Internal Tools · Relational Databases · CLI Tools · Fullstack Development · Frontend Development · Backend Development · Modern Frontend Tooling · JSON · Data Migration · Messaging Systems · Event-Driven Architecture · IntelliJ · Debugging · SQL Server · OpenTelemetry

Software Engineer — Frontend Platform

02/2023 — 09/2025

Flutter Entertainment (FanDuel)

  • Frontend engineer on a microfrontend sportsbook platform; one of few engineers who owned and architected the company's backoffice design system.
  • Replaced the team's bash on-call diagnostics with a Node.js CLI any frontend engineer could extend; it became the default tool and cut mean time-to-resolve by 15% (PagerDuty).
  • Mentored associate developers, contributed to technical hiring, and gave invited lectures on frontend testing at ISEP, UPTEC, and Porto Tech Hub.

React · TypeScript · React Router · Storybook · Jest · Playwright · Feature flags · RAG · Python · Accessibility · web accessibility (WCAG) · micro frontends · Bash scripting · Shell Scripting · Core Web Vitals · LLM-API · LLM Orchestration · agentic workflows · prompt engineering · context engineering · generativ AI · GraphQL · TanStack Form · React Testing Library · Jira · Component-driven Development · React Aria · Observability & Monitoring · Jenkins · code reviews · Application Architecture · GenAI & LLM Solutions · English (Professional Proficiency) · Documentation · OpenAI · Anthropic Claude · End-to-End Development · Clean Code · Internal Tools · Authorization · CLI Tools · npm · Frontend Development · Modern Frontend Tooling · Performance Optimization · JSON · Cursor · AI Agents · Design Systems · IntelliJ · User Experience · Debugging · Model Context Protocol (MCP) · AI Tools · Performance Profiling · AI Technologies · Incident Response · Confluence · Backend For Frontend

Junior Frontend Developer

03/2020 — 02/2023

7egend (Unilabs, Fnac, Portuguese Football Federation, FC Porto)

  • Delivered web workflows for [Unilabs](https://www.unilabs.pt/), [Fnac](https://www.fnac.pt/), the [Portuguese Football Federation](https://www.fpf.pt/) and [FC Porto](https://www.fcporto.pt/pt), to tight agency deadlines.
  • Implemented internationalization support for Unilabs' drive-through COVID-19 testing platform under urgent timelines.

React · TypeScript · Tailwind CSS · i18n · CI/CD · Figma · PHP · Redux · SASS · MUI · SEO · Technical SEO · Azure DevOps · Scrum · Angular · Monorepos & Large-Scale Applications · End-to-End Development · NgRx/NGXS · CLI Tools · npm · Server-Side Rendering · Webpack · Frontend Development · Modern Frontend Tooling · GitLab CI/CD · GitLab · JSON · Single Page Applications · Debugging · Phalcon · Adobe XD · E-commerce · Styled Components · Backend For Frontend

Software Engineer (Internship)

09/2019 — 03/2020

Metric4 (Águas do Tejo Atlântico)

  • Prototyped an AI platform for a machine-vision model optimising urban wastewater management.

Next.js · Feature flags · Python · Bash scripting · Shell Scripting · Azure DevOps · NgRx/NGXS · CLI Tools · Webpack · JSON · Linux · Machine Learning · Computer Vision · Machine Vision · AI/ML · Styled Components · Prototyping

Education

Instituto Superior de Engenharia do Porto

2022 — 2024

Electrotechnical & Computer Engineering (incomplete)

Politécnico do Porto · Porto, Portugal

Focus areas: electronics and automation, energy systems, software and systems design.

Selected Work

Research Projects

Projects I've built in order to test and experiment with AI workflows and emerging technologies.

Research Framework An autonomous, multi-stage research pipeline (scout, research, harvest, note-writer) driven by pluggable LLM executor adapters — Claude, Codex, Cursor, OpenCode, Ollama — behind a single provider-agnostic dispatch surface with per-call cost telemetry. Builds self-citing, machine-queryable Obsidian knowledge vaults from a specification document, with drop-in source modules for GitHub, Atlassian Jira/Confluence, and RSS/Reddit, deterministic quality enforcement (budget caps, credibility domain catalog, wikilink disambiguation), and a seven-tier test pyramid (1,700+ tests) gated in CI.
Home Expense Organizer A collection of scripts to ingest and parse bank statements and invoices to generate information that's easier to analyse

Personal Projects

Things I've been building on my own time out of curiosity and genuine interest in the subject.

Airbus A320 Hydraulics ECAM Page A responsive recreation of the A320's hydraulic ECAM page, simulating fluid behaviour and system states in real time with canvas — with light/dark themes and real-time service worker updates to mimic realistic cockpit conditions, and a modular architecture built to support future integration with the MSFS SDK and backend telemetry. Built out of a long-standing passion for aviation.

Open Source Contributions

Open source repositories I contributed to on my spare time.

FlyByWire Made some minor contributions to the installer frontend

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