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.

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

Experience

Software Engineer — Backend (real-time risk platform)

09/2025 — 06/2026

Flutter Entertainment (FanDuel)

  • Built distributed microservices on the real-time risk and liability pipeline behind every bet placed across multiple US jurisdictions (Java, Spring Boot, Kafka, Cassandra on AWS), with REST API design, hexagonal architecture and TDD.
  • Designed and implemented the approach for migrating a production database from MySQL to Cassandra.

Java · Spring Boot · Kafka · microservices · TDD · MySQL · Cassandra · Docker · AWS

Software Engineer — Frontend Platform

02/2023 — 09/2025

Flutter Entertainment (FanDuel)

  • Frontend engineer on a microfrontend sportsbook platform; architected and maintained the company's backoffice design system.
  • Spearheaded a general-purpose search interface for a new microfrontend platform, replacing siloed trader tools with composable, independently deployable modules.
  • 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).
  • Led the unpacking of Block Settlement end to end while the team's senior engineers were unavailable, drafting the HTML/CSS mocks myself when no designer was available.
  • Mentored associate developers, contributed to technical hiring, and gave invited lectures on frontend testing at ISEP, UPTEC, and Porto Tech Hub.

React · TypeScript · Storybook · Jest · Playwright · GraphQL · micro frontends · design systems · WCAG

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 · Redux · Tailwind CSS · SASS · Angular · Azure DevOps · CI/CD · Figma · i18n

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 · Python · Azure DevOps · Linux

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

Open Source Contributions

Open source repositories I contributed to on my spare time.

FlyByWire Made some minor contributions to the installer frontend

Writing

Get in Touch

Elsewhere