João Oliveira, Developer in Porto, Portugal
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João Oliveira

Verified Expert  in Engineering

Front-end Developer

Location
Porto, Portugal
Toptal Member Since
August 24, 2022

João is a front-end developer with extensive experience in JavaScript and React. Throughout his career, he has shared his expertise and solved problems by contributing to well-established and complex applications, such as Farfetch, creating components from scratch, and designing front-end applications for Polkastarter. João is also a consultant advising and analyzing major projects such as 10up.

Portfolio

Reddit
JavaScript, Front-end Development, HTML, TypeScript, Front-end, CSS, GraphQL...
Personio - Main
React, TypeScript, Front-end, API Integration, Styled-components, SCSS, CSS...
Version Story
React, TypeScript, JavaScript, Bootstrap, SCSS, CSS, Redux, Jest, Enzyme...

Experience

Availability

Full-time

Preferred Environment

MacOS, Visual Studio Code (VS Code), GitHub, JavaScript, HTML, CSS, Scrum, Agile, React, TypeScript, Responsive Web Design (RWD)

The most amazing...

...thing I've worked on is the project for the California Department of Corrections and Rehabilitation.

Work Experience

Senior Front-end Software Engineer

2023 - PRESENT
Reddit
  • Successfully performed accessibility audits, identifying and resolving issues to ensure a more inclusive user experience.
  • Spearheaded the development and enhancement of key widgets and functionalities, resulting in improved user engagement and satisfaction.
  • Contributed significantly to the improvement of test coverage, enhancing the overall quality and stability of the platform.
  • Collaborated with cross-functional teams to identify and address complex technical challenges, fostering a culture of continuous improvement.
  • Actively participated in code reviews, providing constructive feedback and contributing to the overall code quality.
  • Demonstrated a proactive approach in identifying and resolving issues, minimizing downtime and improving the overall efficiency of the development process.
Technologies: JavaScript, Front-end Development, HTML, TypeScript, Front-end, CSS, GraphQL, ECMAScript (ES6), Angular, React, REST, Vue, Polymer, Web Components

Senior Front-end React and TypeScript Developer

2022 - 2022
Personio - Main
  • Worked with an agile international team and took in an all-in-one HR software for small and medium-sized companies.
  • Created convenient tools and workflows to enable delivery teams to contribute to the design system (e.g., linter rules, pipelines, playground environments).
  • Collaborated and aligned with technical and non-technical stakeholders, e.g., front-end engineers, product designers, product managers, and engineering managers.
  • Advocated the adoption and implementation of the design system across teams.
  • Supported engineers across delivery teams to unblock their UI library challenges.
  • Directly contributed to Personio codebase as a front-end engineer and as part of a product team.
  • Identified, documented, and communicated technical improvements within my area of responsibility in the team.
  • Supported the development and reinforcement of front-end engineering standards and guidelines.
  • Closely collaborated with technical (back-end, QA, and infrastructure) and non-technical (product, design) roles to understand and challenge end user requirements and ultimately translate these into effective technical solutions.
  • Helped with selecting, onboarding, and coaching junior members of the team.
Technologies: React, TypeScript, Front-end, API Integration, Styled-components, SCSS, CSS, Modular CSS, Nx, Monorepos, Responsive Web Apps, Figma, DOM, REST, Visual Studio Code (VS Code), HTML, JavaScript, Scrum, Agile, Lodash, JSON, REST APIs, Git, Sass, ECMAScript (ES6), Responsive Web Design (RWD), Pixel Perfect, UI Development, User Interface (UI), Jest, Enzyme, ESLint, Next.js

Senior Front-end Engineer

2022 - 2022
Version Story
  • Developed the front end of an intuitive system for organizing document histories and generating comparisons.
  • Created and contributed design ideas for multiple UI widgets, including toolbars, color pickers, version tiles, dashboards, context menus, and forms.
  • Provided assistance to fix urgent bugs in the app and the public website as needed.
  • Made a component library and playground from scratch to showcase all the components I was creating.
  • Developed unit tests and component snapshot tests using Jest and Enzyme.
Technologies: React, TypeScript, JavaScript, Bootstrap, SCSS, CSS, Redux, Jest, Enzyme, Styled-components, Responsive Web Apps, Data Visualization, Figma, Chakra UI, DOM, REST, Visual Studio Code (VS Code), HTML, Lodash, JSON, REST APIs, GitLab, Git, Sass, API Integration, ECMAScript (ES6), Responsive Web Design (RWD), Front-end, Pixel Perfect, UI Development, User Interface (UI), ESLint

Senior Front-end Engineer

2022 - 2022
Conductive
  • Helped develop and design well-strutted web applications using modern technologies like React, TypeScript, and Storybook.
  • Created a React component library using Storybook from scratch.
  • Implemented Web3 integrations for wallet connections and contract integrations for multi-chain support.
  • Shipped new features rapidly within a highly collaborative team.
  • Developed unit tests and component snapshot tests using Jest and Enzyme.
Technologies: React, TypeScript, JavaScript, SCSS, Storybook, Web3.js, MetaMask, CSS, Styled-components, Jest, Enzyme, Responsive Web Apps, Data Visualization, Figma, Chakra UI, DOM, REST, Visual Studio Code (VS Code), HTML, Highcharts, Lodash, JSON, REST APIs, GitLab, Git, Bootstrap, Sass, API Integration, ECMAScript (ES6), Responsive Web Design (RWD), Front-end, Pixel Perfect, UI Development, User Interface (UI), ESLint, Tailwind CSS

Senior JavaScript Engineer

2021 - 2022
10up
  • Contributed to various international projects, including Financial Times, Hello! magazine, California Department of Motor Vehicles, and California Department of Corrections and Rehabilitation.
  • Developed and provided technical support and advice on the architectural concepts behind React, including state and data management, JSX, building componentized systems, and webpack.
  • Wrote modular, extensible, and performant modern JavaScript.
  • Estimated the JavaScript and React work and modularized goals into clearly defined, executable tasks.
  • Identified performance and quality issues across the 10up digital ecosystem and provided solutions.
  • Used Chrome DevTools to investigate and fix front-end rendering performance issues and computationally intensive bottlenecks.
  • Contributed to the alignment of engineering deliverables with client business objectives.
Technologies: React, Next.js, Storybook, CSS, Sass, Amazon S3 (AWS S3), HTML, Git, WordPress, AWS Amplify, Node.js, Firebase, Pixel Perfect, SCSS, Responsive Web Design (RWD), Front-end, UI Development, Material UI, API Integration, ECMAScript (ES6), JavaScript, Ionic, JSON, REST APIs, Redux, OAuth, Docker, MUI CSS, User Interface (UI), Jest, Enzyme, Styled-components, eCommerce, GraphQL, Responsive Web Apps, Figma, DOM, REST, Visual Studio Code (VS Code), APIs, TypeScript, Lodash, GitLab, Bootstrap, ESLint, Full-stack

Lead Front-end Engineer

2021 - 2022
Polkastarter
  • Managed a remote international team to build the front end of a protocol for cross-chain token pools.
  • Built the entire front-end application in React and TypeScript and extended a React component library in Storybook.
  • Implemented Web3 integrations for wallet connections and contract integrations for multichain support.
  • Used Polkastarter.js open-source middleware that connects with multiple blockchains.
  • Conceived, designed, built, and launched new user-facing features.
  • Developed unit tests and component snapshot tests using Jest and Enzyme.
Technologies: React, TypeScript, JavaScript, Web3.js, MetaMask, Storybook, Bootstrap, CSS, Sass, Stimulus, Agile, Scrum, Firebase, Pixel Perfect, SCSS, Responsive Web Design (RWD), Front-end, UI Development, API Integration, ECMAScript (ES6), HTML, Chart.js, JSON, REST APIs, User Interface (UI), Jest, Enzyme, Styled-components, Responsive Web Apps, Data Visualization, Figma, DOM, REST, Visual Studio Code (VS Code), APIs, Highcharts, Lodash, Git, ESLint, Tailwind CSS, Full-stack

Front-end Engineer

2020 - 2021
Farfetch
  • Participated in developing the front end of an online luxury fashion retail platform by working mainly on the login platform.
  • Evaluated new technologies and implemented processes to ensure consistent quality of deliverables.
  • Defined the architecture and development of one of the projects and implemented pages and functionality according to provided designs.
Technologies: React, Next.js, TypeScript, JavaScript, Storybook, HTML, CSS, Pixel Perfect, SCSS, Responsive Web Design (RWD), Front-end, UI Development, Material UI, API Integration, ECMAScript (ES6), JSON, REST APIs, Redux, OAuth, Docker, MUI CSS, User Interface (UI), Agile, Styled-components, eCommerce, Responsive Web Apps, Figma, DOM, REST, Visual Studio Code (VS Code), APIs, Scrum, Lodash, GitHub, Git, Bootstrap, Sass, Jest, Enzyme, ESLint

Front-end Engineer

2017 - 2020
Techbiosis
  • Built a web application while working in fintech with remote agile teams to help companies create and manage their fund portfolios more efficiently.
  • Refactored a large front-end application code to make it more modular and reusable.
  • Communicated and collaborated with back-end developers to fix bugs.
  • Wrote form-based pages to enable dynamical change as data was entered and REST API was queried.
  • Developed several UX filtering controls to facilitate entering and reviewing metrics.
  • Used Highcharts to develop user-friendly, reliable, and secure data visualizations for investment funds.
  • Developed unit tests and component snapshot tests using Jest and Enzyme.
  • Encouraged a commit policy by implementing Git hooks.
  • Involved in developing full-stack mobile applications for iOS and Android using React Native.
Technologies: React, JavaScript, TypeScript, HTML, CSS, React Native, Node.js, Highcharts, Lodash, GitHub, Git, Firebase, Pixel Perfect, SCSS, Responsive Web Design (RWD), Front-end, UI Development, API Integration, ECMAScript (ES6), Ionic, JSON, REST APIs, Redux, OAuth, D3.js, Docker, Material UI, MUI CSS, User Interface (UI), Agile, Enzyme, Jest, Styled-components, eCommerce, Responsive Web Apps, DevExtreme, Data Visualization, .NET Core, APIs, Visual Studio, DOM, REST, Visual Studio Code (VS Code), Scrum, Bulma, Bootstrap, Sass, ESLint, Full-stack

CPR.PT—Cardiopulmonary Resuscitation Personal Trainer

https://simulacao.med.up.pt/projetos-em-desemvolvimento/
CPR.PT is intended to be a low-cost cardiopulmonary resuscitation training add-on used with a dummy to collect feedback and score technical maneuvers.

I worked on this project as part of my internship with FMUP, designing and developing the application's back end and front end.

Personio: Widget Replatforming

https://www.personio.com/
I worked with an agile international team and took in an all-in-one HR software for small and medium-sized companies. The project's main goal was to migrate the whole app from a monolith to a monorepo architecture. Another goal was to improve the UI based on new designs. I implemented several widgets (Workflows, Approvals, My Absences Widget, among others) following the company's guidelines and with almost 100% test coverage as a senior front-end engineer. Additionally, I developed tools and workflows that enabled delivery teams to contribute to the design system (e.g., linter rules, pipelines, playground environments).

10UP | California DMV

https://www.dmv.ca.gov/
I worked with a remote team on the California Department of Motor Vehicles (DMV) platform. You can apply for an ID, register a vehicle, renew a driver's license, and more on this platform. I worked as a senior front-end engineer in implementing new functionalities and improving the performance of the application.

Polkastarter

https://polkastarter.com/
As the lead front-end developer, I was responsible for the architecture and implementation of the front end of a protocol for cross-chain token pools and also how it would connect with the back end. I managed a small team of front-end developers (three developers). I worked closely with the CTO at the time, Tiago Martins. Together, we implemented a brand-new design, added features, and migrated the app from Stimulus to React with TypeScript. To document the component library, we opted for Storybook. I also implemented Web3 integrations for wallet connections and contract integrations for multichain support. I developed unit tests and component snapshot tests using Jest and Enzyme. I created and assigned tasks to team members. I created convenient tools and workflows to enable team members to contribute to the design system (e.g., linter rules, pipelines, playground environments).

I collaborated and aligned with technical and non-technical stakeholders, e.g., designers, product designers, product managers, and engineering managers.

Aflo Analytics

https://afloanalytics.com/
Served as a front-end developer building a mobile healthcare application using React and Ionic. A combination of artificial intelligence and sensors was used in the app to automate the inhaler technique. The device facilitates medication delivery deep into the lungs, improving outcomes for asthma, COPD, and cystic fibrosis patients. I worked on the authentication and authorization process on the dashboard and on several widgets to show the feedback on the inhalations and other helpful information.

Languages

JavaScript, HTML, CSS, TypeScript, Sass, ECMAScript (ES6), SCSS, GraphQL

Frameworks

Bulma, Bootstrap, Jest, Next.js, Stimulus, Ionic, Material UI, Redux, MUI CSS, Tailwind CSS, React Native, .NET Core, Angular

Libraries/APIs

React, Highcharts, Lodash, REST APIs, DevExtreme, Node.js, Web3.js, AWS Amplify, Chart.js, D3.js, Vue, Polymer

Tools

Git, Figma, Visual Studio, GitLab, GitHub, MetaMask

Paradigms

Responsive Web Design (RWD), REST, Agile, Scrum, Modular CSS

Platforms

Visual Studio Code (VS Code), Firebase, Docker, WordPress, Linux

Storage

JSON, Amazon S3 (AWS S3), Datadog

Other

Storybook, API Integration, Pixel Perfect, Front-end, UI Development, User Interface (UI), Styled-components, Enzyme, Responsive Web Apps, Chakra UI, DOM, OAuth, Data Visualization, APIs, eCommerce, Nx, Monorepos, ESLint, Full-stack, Front-end Development, Web Components

2014 - 2017

Bachelor's Degree in Software Engineering

Polytechnic of Porto—School of Engineering (ISEP) - Porto, Portugal

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