Rens Poesse, Developer in Colombia
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Rens Poesse

Verified Expert  in Engineering

Progressive Web Applications (PWA) Developer

Location
Colombia
Toptal Member Since
June 25, 2018

Rens is a full-stack developer with over a decade of experience leading teams, designing complex systems, and communicating effectively. He also has a background in psychological research and statistics. Having worked for corporate clients, in academics, and for startups, Rens has a deep understanding of various stakeholders while maintaining a young, creative mindset. He was named one of the most promising tech talents according to TNW.

Portfolio

Rens Poesse
R, Webpack, Tailwind CSS, Sass, CSS3, Server-side Rendering (SSR), React...
Kinder Donations
Webpack, Bootstrap, Sass, CSS3, React, Vue, JavaScript...
Mobypicture
Android, Bootstrap, HTML, CSS3, Sass, Backbone.js, React, JavaScript, Java, PHP

Experience

Availability

Part-time

Preferred Environment

JetBrains, Linux, MacOS, Git

The most amazing...

...thing I've built is a live industrial tracking-and-tracing system that integrates automatic vehicle identification, weighing software and PLC communication.

Work Experience

Freelance Developer

2015 - PRESENT
Rens Poesse
  • Developed various applications; using Node.js, Laravel, Vue.js/React, SSR, Tailwind CSS, and Heroku or Amazon Web Services.
  • Produced metrics on student matching procedures by analyzing big data in R—generating an effectiveness report.
  • Rapidly prototyped ideas for new apps, including dashboards, chatbots, and voice interfaces.
  • Worked on brand activations for large clients, including IKEA, Rituals, and HEMA.
  • Helped to hire candidates for clients by developing exercises for technical interviews and assessing candidates on multiple relevant skills.
Technologies: R, Webpack, Tailwind CSS, Sass, CSS3, Server-side Rendering (SSR), React, Nuxt.js, Vue, JavaScript, DevOps, Amazon Web Services (AWS), Vagrant, Heroku, Docker, Redis, MongoDB, SQL, C#, PHP, Node.js

CTO

2016 - 2017
Kinder Donations
  • Managed a scalable Docker stack on Amazon Web Services with PHP, MySQL, MongoDB, and Redis.
  • Built APIs with OAuth implementations and also integrating Algolia search and Stripe payment processing.
  • Created reactive web components with Vue.js and React which increased reusability.
Technologies: Webpack, Bootstrap, Sass, CSS3, React, Vue, JavaScript, Amazon Web Services (AWS), Docker Swarm, Docker, Redis, MongoDB, SQL, PHP, Node.js

Front-end Lead

2015 - 2017
Mobypicture
  • Led the front-end development of a content management system using Backbone.js and developed a corresponding Android app.
  • Reduced image-loading time by up to 50% by implementing server-side image processing which led to a smoother user experience.
  • Developed various front-end widgets, including a 3D map view that uses Mapbox GL to provide a flight journey through photos taken throughout the world.
Technologies: Android, Bootstrap, HTML, CSS3, Sass, Backbone.js, React, JavaScript, Java, PHP

Software Engineer

2015 - 2015
Locatienet
  • Detected methods of transport by utilizing geolocation data retrieved from native Android and iOS apps.
  • Visualized real-time data on a per-user dashboard which enabled data-driven business decisions.
  • Completely redesigned and rebuilt a website that provides traffic information and route planning, much like Google Maps.
Technologies: SQL, .NET, CSS, HTML, JavaScript, iOS, Android, GIS

Research Assistant

2014 - 2015
University of Amsterdam
  • Simulated a parameter estimation for linear ballistic accumulator (LBA) models.
  • Wrote an article that was published in the British Journal of Mathematical and Statistical Psychology.
  • Developed an LTI integration that provides a way by which Qualtrics surveys can be included in a Coursera course for the purpose of A/B testing.
Technologies: PHP, SPSS, R

Software Engineer

2009 - 2013
Brainpact Industrial Automation
  • Developed logistic solutions using .NET and automatic vehicle identification technology which resulted in better-facilitated stock auditing.
  • Automated industrial traffic lights by optimizing weighing software and PLC communication layers.
  • Built an ASP.NET maintenance management system with a C# back-end that allows planning recurrent jobs, order placement, and facility management.
Technologies: PLC, Java, Microsoft SQL Server, C#, .NET

Duolingo

https://duolingo.com
As a front-end contractor, I worked on next-generation education technology that helps millions of people learn on mobile and desktop web.

Responsibilities:
• Collaborated on software projects with product design and backend aspects.
• Developed, released, and maintained web applications.
• Manage individual project priorities, deadlines, and deliverables.

Hello Chef

https://hellochef.me
I received this review for the work I did for Hello Chef.

"Rens was the key figure in a team of developers that built our system from scratch. While he mainly handled front-end, it's obvious that he has vast experience in all key areas of software development. Rens kept the entire team organized and focused and ultimately we built a very reliable system. If you're looking for a senior professional to lead on the development of your next complex software project, speak to Rens."

- Ahmed Al Akber, CEO, Hello Chef

Kubernetes and Docker Swarm with CI/CD

I have set up Kubernetes and Docker Swarm clusters for multiple clients, converting applications to be run in containers, setting up monitoring and centralized logging, configuring replicas, load balancing and automated zero downtime deployments with a CI/CD pipeline.

Hack Partners

I developed dashboards and data visualizations for rolling stock companies, enabling analysis of speed, fuel consumption, etc. of train carriages.

Technologies: React, Plotly, Grafana

Pac-Man, Flappy Bird, and Doodle Jump

For a campaign of a large brand in the soccer branch, I developed mobile-first adaptations of Pac-Man, Flappy Bird, and Doodle Jump. These were directly advertised on Instagram and were hosted to support large amounts of traffic.

Technologies: Canvas, Vue.js, Hammer.js, Howler.js, EaselJS, Amazon Web Services

Forget the Fish

https://growapp.today
I completely rewrote the GrowApp using React. I increased browser support, added localization, and implemented the camera integration.

With the Grow app, people can make time-lapse animations of the environment through seasons and years, by regularly taking pictures with your smartphone from the same location. These pictures are used to help scientists who investigate the effect of climate change on nature.

Technologies: React, WebRTC, Onion Skinning

Real-time Waiting List and Dashboard

https://ugohq.com/
As part of their new product launch, I developed a real-time online waiting list app for U GO where people could sign up to purchase the product and get notified immediately when it was their turn. Using a custom admin dashboard, the marketing team could also manually move people onto the list.

Technologies: Vue.js, SSR, Nuxt.js, Tailwind CSS, WebSockets, Heroku
2016 - 2019

Master of Science (MSc) Degree in Behavioral Data Science

University of Amsterdam - Amsterdam, Netherlands

2013 - 2016

Bachelor of Science (BSc) Degree in Psychological Methods

University of Amsterdam - Amsterdam, Netherlands

Libraries/APIs

Node.js, jQuery, Vue, React, Vuex, Chart.js, React Redux, Socket.IO, Reselect, Immutable.js, Backbone.js, Google Cloud API, Redux-Saga

Tools

PostCSS, Docker Swarm, Docker Compose, Webpack, CircleCI, SPSS, Git, Mongoose, Plotly, Grafana, JetBrains, GIS, Vagrant

Frameworks

Vue SSR, Tailwind CSS, Nuxt.js, Bootstrap, Redux, Laravel, Express.js, Koa, .NET, PixiJS, React Native

Languages

CSS, SQL, HTML, Sass, JavaScript, PHP, Less, TypeScript, R, C#, CSS3, Java, GraphQL

Paradigms

Reactive Programming, Object-oriented Programming (OOP), Concurrent Programming, Functional Programming, DevOps

Platforms

Windows, MacOS, Docker, Android, Linux, Amazon Web Services (AWS), AWS Lambda, Kubernetes, WordPress, Heroku, iOS, Firebase

Storage

MySQL, Microsoft SQL Server, MongoDB, NoSQL, Redis, Memcached

Other

Responsive Design, Progressive Web Applications (PWA), Data Visualization, Data Analysis, Architecture, Payment Gateways, WebSockets, Learning Tools Interoperability (LTI), PLC, Server-side Rendering (SSR), Voice UI Design, Machine Learning, Serverless

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