Daniel Araujo, Developer in Porto, Portugal
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Daniel Araujo

Verified Expert  in Engineering

Full Stack Developer

Porto, Portugal
Toptal Member Since
September 1, 2019

Daniel is an engineer experienced in the development of large-scale web products. He is a test-driven development advocate and lover of reliable, highly-scalable, and performant software solutions. As a person and developer, Daniel is self-motivated, eager to learn, and happy to collaborate and provide solutions.


NumberAI (via Toptal)
Python, HTML, CSS, JavaScript, Cypress, Jest, React Native, React
Paddy Power Betfair
CSS, Ruby, Chef, Jenkins, Protractor, Jest, HTML, AngularJS, Storybook, Redux...
Docker, Apache ZooKeeper, Scala, Guice, Guava, Java




Preferred Environment

MacOS, Git, Visual Studio Code (VS Code)

The most amazing...

...piece of software that I've developed was a real-time machine learning web application that determined the emotion of the user based on camera input.

Work Experience

Front-end Engineer

2019 - 2020
NumberAI (via Toptal)
  • Built the Eatmoji Menu Builder (a dynamic restaurant menu builder) using React. This product helped save the support team hundreds of hours from the first week it was launched.
  • Shipped end-to-end features in React, React Native, and Python in NumberAI's production codebase.
  • Helped bring a lot of visual polish to NumberAI's apps.
  • Developed several end-to-end tests using Cypress, in addition to unit and integration tests.
Technologies: Python, HTML, CSS, JavaScript, Cypress, Jest, React Native, React

Full-stack Engineer

2018 - 2019
Paddy Power Betfair
  • Maintained and modernized a legacy web and mobile application.
  • Developed betting features for both mobile and desktop web applications.
  • Configured different deployment environments using Jenkins for CI and Chef.
  • Developed Node.js services (back end for front end).
  • Built betting features for a mobile sportsbook Betfair application.
Technologies: CSS, Ruby, Chef, Jenkins, Protractor, Jest, HTML, AngularJS, Storybook, Redux, Node.js, ECMAScript (ES6)

Back-end Engineer

2017 - 2017
  • Worked for Feedzai, which provides near real-time machine learning through a multi­threaded, distributed and fault­-tolerant system.
  • Worked on the leading product engineering team which developed cutting edge features of the real-time data processing and machine learning on the in-­house engine.
  • Developed a PCI-compliant credit card storage engine.
Technologies: Docker, Apache ZooKeeper, Scala, Guice, Guava, Java

Full-stack Engineer

2016 - 2017
Paddy Power Betfair
  • Worked in a large-scale web product using Scrum.
  • Developed E2E tests using Protractor.
  • Used Jenkins for CI and Chef for configuring different deployment environments.
  • Worked as part of a cross-product team that developed a core business reusable component.
  • Developed Node.js services (back end for front end).
  • Developed betting features both for mobile and desktop web applications.
Technologies: Ruby, Chef, Jenkins, Mocha, RxJS, Protractor, AngularJS, Redis, Node.js, ECMAScript (ES6)

Software Engineer | Researcher

2015 - 2016
  • Worked for Performetric: a real-time monitoring system that allows the management of mental fatigue in a non­invasive way. At the time Performetric was already backed by scientific knowledge and was developing a scalable product.
  • Architected, designed, and implemented the data processing engine. In particular, focusing on data ingestion, batch processing, and real-time analytics.
  • Published two scientific papers.
Technologies: JMH, MongoDB, Java


2015 - 2015
ACICE ­Esposende’s Commercial Union
  • Developed an API for interaction with ACICE’s database (using Laravel).
  • Designed and implemented a hybrid mobile app using Ionic and AngularJS.
Technologies: Laravel, AngularJS, Ionic

Software Developer

2014 - 2015
  • Developed some modules for interaction with Twitter and LinkedIn web APIs.
  • Designed and implemented indexers and search strategies using the Spinque engine.
  • Implemented a mobile web app for navigation on the aggregated content using AngularJS.
  • Researched the possibility of using Spinque search strategies and user contextual data in order to improve the UX.
Technologies: AngularJS, JavaScript, Java

Web Developer

2013 - 2013
Freelance Work
  • Developed for the web on behalf of a client in the domain of transportation.
Technologies: Twitter, Bootstrap, jQuery, Ruby on Rails (RoR)

Undergraduate Researcher

2012 - 2012
CCTC | Computer Science and Technology Center
  • Worked as a junior researcher on an evolutionary algorithms library.
  • Built, with guidance, a graphical user interface (GUI) for executing and fine-tuning a runtime set of configurations; at the time was guided by a professor and a PhD student.
Technologies: Swing, Java

Apartment Rental Management Application

I build the back end and front end for an application that manages apartment rentals. The back end was developed using Node.js (Express.js, MongoDB), and the front end used React (hooks).

The application allows third-party authentication and role-based authorization. The set of functionalities encompassed user management, apartment management, and searches (via attributes and via geolocation on a map).


JavaScript, ECMAScript (ES6), Scala, CSS, HTML, Java, Python, Ruby, TypeScript, SQL, Haskell


React, REST APIs, Node.js, jQuery, RxJS, Guava


Express.js, AngularJS, Redux, Bootstrap, Swing, Ionic, JMH, React Native, Cypress, Next.js, Ruby on Rails (RoR), Spring Boot, Protractor, Angular, Jest, Guice, Laravel


Git, Mocha, Figma, Java Concurrency, Postman, Docker Compose, Jenkins, Webpack, Chef, Mongoose, Apache ZooKeeper


RESTful Development, Functional Programming, Testing


Web Development, Storybook, Computer Engineering, Software Engineering, Enzyme, Algorithms, TypeORM, Machine Learning, ETL Development


MacOS, Twitter, Linux, Docker, Heroku, Visual Studio Code (VS Code)


MongoDB, JSON, Redis, PostgreSQL

2013 - 2016

Master's Degree in Computer Engineering

Minho University - Braga, Portugal

2014 - 2015

Earned Credits as an Exchange Student towards a Master's Degree in Software Engineering

Universiteit van Amsterdam - Amsterdam, Netherlands

2010 - 2013

Bachelor's Degree in Computer Engineering

Minho University - Braga, Portugal