Hi, my name's Jack.

I'm a senior fullstack developer with more than 7 years experience. I live in Berlin, have founded my own successful startups, and worked for Silicon Allee's biggest brands. I'm currently considering contracts in Berlin.

Hall of fame

SoundCloud, Fullstack

Senior fullstack developer. Used Scala, NodeJS, Golang, Docker, React and Rails to serve over 50k requests per second and 150million users.

GoEuro, Backend Lead

Backend developer working on APIs and Payments using Java, Scala, Spring, Play, Mongo, AWS, and Postgres.

EyeEm, Fullstack Lead

Planned and implemented a fullstack rewrite of the EyeEm web platform building a responsive isomorphic React app for 20million users.

Notable contracts

Croove, Backend Lead

Lead backend for Daimler's car sharing service Croove. Built using Scala, AKKA, NodeJS, Golang, AWS SNS and Lambda.

Geeny, Backend

Backend developer at Telefonica's German IoT branch, Geeny. Built an IoT gateway using Scala, AKKA, NodeJS, Golang, AWS IoT and Lambda.

Your company?

I could bring a wealth of practical experience and technical expertise to your business. I write clean, pragmatic, maintainable code and communicate clearly. I'm a team player and want to see my clients succeed. From building my own companies and working in firms large and small I know how to balance priorities and deliver results.

Main skills

Java, Scala, AKKA, Spring, NodeJS, ES6+, Golang, Rails, React, Vue, Mongo, Typescript, SQL, Postgres, AWS, Docker, CSS3, HTML5, UNIX/GNU, Android, communication, pragmatism, confidence, and learning new systems.

Companies founded


A free API for end-to-end testing transactional emails. With MailSlurp you can generate random email addresses programatically, to can send and receive emails during tests. It's perfect for testing OAuth signup flows, email notifications, and automated responses.

I created every aspect of MailSlurp, making heavy use of AWS, pub-sub queues, Java 8 and Typescript React. I also write blog posts and market the service.

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A free, private, secure VPN for Chrome. When enabled it routes requests through American and British servers so that users can browse from those countries. It is profitable via affiliate linking.

I designed MakeMe's look and message, built the website and Chrome extension, and developed the infrastructure. The servers handle very high bandwidth and must scale automatically, while evading IP blacklists — it's a challenging task!

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My hobby is 3D-rendering, which requires powerful GPUs. My MacBook didn't have those, so I built an online service for rendering in the cloud using AWS EC2 GPU instances.

The first version was called 3drendercloud and used StripePayments and Firebase to let users signup, load credits, and render in the cloud. It was a very complex app, betting on the EC2 instances marketplace to get the lowest price GPUs, transfering files to instances, rendering via an API, and saving images to S3. It supported Blender, Maya, C4D, and 3DSMax.

It was profitable, but in 2018 I started a rewrite to make it simpler to maintain and use: JellyRender was born! Through this project I learned an immense amount about AWS and had to test every aspect of the app (as money was involved).

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As you may have noticed — I like to make webapps. But I'm often at a loss for names. That's why I threw together DomainPecker. An animal-themed startup domain-name generator.

This was an experiment in making a fully functional SaaS app as fast as possible. I chose VueJS and serverless AWS Lambda to keep costs and complexity down. It turned out to be a great choice, taking a prototype to production in days.

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GLS (Postal Service), Project lead and lead developer (Contract)

Java, Spring, Node, React, AWS (SQS, SNS, SES, CloudFormation, Cognito)

I was employed as project lead and lead developer at GLS Labs to develop complex experimental apps for the postal service. There was a heavy focus on AWS and rapid prototyping with Spring Boot, React and Vue. Projects also used Machine Learning and language heuristics for parsing and transforming text. It was a great role that tested my skills in leadership, communication, and problem solving.

October 2017 - January 2018 (Contract)

Croove (Daimler), Lead backend developer (Contract)

Scala, AKKA, NodeJS, GO, AWS, Firebase, Postgres, Mongo, SNS

I worked as a contractor for Daimlers mobility startup Croove. letscroove.com allows people to rent cars from other users in Germany. I wrote APIs for payments, bookings, and customer service using AKKA, AWS SNS, Go, Scala, and NodeJS (Flow). I also assisted in hiring. The company was acquired by Turo in October.

July 2017 - September 2017 (Contract)

My own startups, Founder

AWS, Firebase, Docker, Java, Scala, React, Vue, Node

At one point I left startups to start my own. I built a range of online services, including a profitable online 3D rendering service called 3drendercloud. I created every aspect of it, from development to design and marketing campaigns. The infrastructure was built in Scala Play and AKKA. It dynamicallly allocated AWS EC2 GPU machines to customers and remotely ran rendering software on them. It was a fantastic learning experience. I advertised with Google Adwords, Facebook, Youtube and Twitter. I handled payments via Stripe and logins via Firebase. Everything else was done programmatically in AWS. I learned a great deal about managing time and priorities. These services are now healthy and self-sustaining, which means they don't intefere with daily work.

April 2017 - ongoing

Geeny (Telefonica), API and IoT developer (Contract)

Scala, Java 8, AKKA, NodeJS, AWS IOT, Firebase, Postgres, Mongo, Lambda

I worked as a contractor for Telefonica Germany's R&D offshoot Geeny. I wrote APIs in Scala and Node that managed a complex IoT ecosystem of custom hardware built on the Amazon IOT platform.

January 2017 - April 2017 (Contract)

SoundCloud, Fullstack Engineer

Scala, Java, NodeJS, Golang, Ruby

I wrote Scala APIs and Node applications on an epic scale at SoundCloud. With over 150million users and hundreds of microservices, code had to be well tested and of the highest quality. I learned invaluable skills in communication, code quality, infrastructure, and debugging large applications. I became the lead developer on the Core Web team responsible for 150 servers and the code behind soundcloud.com.

April 2016 - January 2017

GoEuro, Senior Java API Developer

Java, Scala, Spring, Play, AKKA

GoEuro is an agile and energetic Berlin startup that brings bus, train, and air travel together in one place. I worked as a senior backend Java engineer designing and building a brand new RESTful API, which was consumed by many applications and thousands of users daily. It also handled tens of thousands of euros in payments and had to be extremely secure and robust. It called many external parties, and dealt with sensitive information such as addresses and payments. It was a critical system, so bullet-proof testing and clear code planning were paramount.

February 2015 - October 2015

MoreSleep, Tech Lead (Contract)

DevOps, Wordpress, Docker

I served as Tech Lead at the Berlin digital agency MoreSleep. I assisted in hires, managed the developer team, scoped projects, and lead development. I also used my experience in larger companies to modernize the studio's workflows and implement new development and deployment architectures.

October 2015 - March 2016

EyeEm, Fullstack Node Engineer

NodeJS, React, ES6, Flux, PHP

EyeEm is one of the most famous startups in Germany. I worked there as a full stack engineer building a NodeJS-React isomorphic single page web app to serve 20 million users. It was a complex project with many challenges around responsive imagery, page load times, and asset size. We succeeded in making a fast and responsive application on all platforms.

June 2014 - February 2015

Monkii, Lead Frontend Developer

Backbone, Angular, C#, PHP, jQuery, Android

Monkii is a leading digital agency in Melbourne were I worked for two great years as lead front-end, mobile and Wordpress developer.

May 2012 - May 2014

Instinct, Frontend and Wordpress Developer

Backbone, jQuery, PHP, Wordpress

Instinct are the makers of the famous WP-eCommerce plugin. I worked on the plugin and gained a deep understanding of Wordpress core and the plugin ecosystem.

December 2011 - April 2012

Computers For People, Android Developer

Android, Java, C#, PHP, Wordpress

Built four enterprise Android apps along with several Wordpress projects.

May 2011 - April 2012

Paperkite, Android Developer

Android, Java

Helped build the official All Blacks Android app in New Zealand.

January 2011 - May 2011

BSc in Molecular Biology with Computer Science

Studied at Victoria University in Wellington New Zealand. I originally planned to enter BioInformatics (programmatic DNA sequencing and protein folding) but ended up enamoured of software development. I used my studies in Computer Science to enter the workforce and the rest is history.

January 2007 - January 2011