Hello, my name is Gert-Jaap. I have been developing software since my childhood years. This started on our MSX home computer in MSX-BASIC. During high school, I started my professional development carreer at a company called Decos, a Dutch software company. I continued gaining professional experience at Decos while simultaneously studying Computer Science from The Hague University of Applied Sciences.
After graduating, I continued my professional carreer at Decos, in various roles, where I worked for nearly 20 years developing and architecting front- and backoffice systems used by local and regional governments.
In 2017 I decided I wanted to specialize myself in blockchain technology. Having used Bitcoin since early 2013, I wanted to feed my appetite for learning this technology in-depth. I joined the (volunteer) development team of an open-source altcoin Vertcoin, whose underlying technology is very close to Bitcoin. My attachment to Vertcoin to this date helps gain practical experience in cryptocurrency development by maintaining an actively used and deployed cryptocurrency network.
In 2018, I realized that the hunger for Bitcoin and blockchain development was too big to be satisfied in my employment role, and me and Decos decided to part ways. I started my own company Blocksource, in which I provide advise, design and development services in a variety of blockchain technologies.
I joined the Digital Currency Initiative at MIT in April of 2018 as my first contracting job, where I (still) work on various Bitcoin-based software such as Discreet Log Contracts, Lightning Network and lesser known protocols such as B-Verify. I also worked on ZKLedger, which is a privacy-preserving auditable ledger using zero-knowledge proofs. At the moment, I’m working on a project for the DCI called PoolDetective, that monitors mining pools on Bitcoin and 10 other proof-of-work cryptocurrencies.
All my current and past projects both in and out of blockchain technology can be found on my Portfolio page.
Current roles
MIT Digital Currency Initiative
Software Developer (Freelance)
(Since April 2018)
Working with the Digital Currency Initiative as a Software Developer, focusing on public blockchains. Currently working on a project called PoolDetective, which monitors the behavior of mining pools on Bitcoin and 10 other proof-of-work cryptocurrencies.
Generally speaking, the work involves developing prototype implementations of technology researched at the DCI.
Past projects for the DCI include Discreet Log Contracts, Lightning Vending Machine, B-Verify, ZKSigma / ZKLedger
Sagittae
Software Developer (Freelance)
(Since October 2018)
Working with Sagittae as a Software Developer. Sagittae introduces mutual risk-sharing based on distributed ledger technology. It is a decentralized and revolutionizing alternative to traditional insurance, completely eliminating the need for expensive and bureaucratic insurance conglomerates and costly middleman structures.
For Sagittae, I am responsible for developing their Ethereum based blockchain components. This includes development of a utility token, smart contract and accompanying backend API’s to allow the Sagittae front-end to communicate with the blockchain. Software has been deployed on testnet satisfactory and is pending a mainnet rollout.
Vertcoin
Developer (Volunteer)
(Since April 2017)
Vertcoin was my entry into learning blockchain technology. The development team of Vertcoin was very welcoming and given that their technology is very closely related to bitcoin it allowed me to learn about the fundamentals of bitcoin development by providing hands-on experience.
Since becoming attached to the Vertcoin project as a volunteer developer, I have worked on various projects either based on included in the Vertcoin core network software. The most notable work is the One-Click Miner, Verthash and the Lyra2REv3 hardfork
Used technology: Bitcoin, C++, Go, VueJS
Snoeks Automotive BV
Software Developer (Freelance)
(Since 2006)
Snoeks Automotive is the world’s leading partner for car manufacturers to extend their product range in Light Commercial Vehicles. For Snoeks, I developed their Customer Portal in React and backend in C# .NET.
Whilst this is not related to blockchain technology, I have worked with Snoeks Automotive for a long time and am happily maintaining the software I built for them.
Used technology: C# .NET, React
Decos
Blockchain Specialist (Freelance)
(Since May 2018)
Investigating the possibilities of leveraging blockchain technology within the products offered by Decos to its clientele of government and non-profit organizations.
Investigated the possibilities for using blockchain for processes like auditing, digital signatures. Built an integration between Decos JOIN and a digital signature blockchain-as-a-service platform.
Set up a cryptocurrency mining operation involving several ASIC miners as well as self built GPU mining installation. Built the full dashboarding required to monitor the mining operation, including the ability to switch the GPU miners from one cryptocurrency to the other on-the-fly. Maintained this installation until summer of 2019, when it was decommissioned.
Used technology: Bitcoin, blockchain, cryptocurrencies, cryptocurrency mining
Past roles
Decos
Blockchain Specialist
(October 2017 - May 2018)
Investigating the possibilities of leveraging blockchain technology within the products offered by Decos to its clientele of government and non-profit organizations.
Investigated the possibilities for using blockchain for processes like auditing, digital signatures. Built an integration between Decos JOIN and a digital signature blockchain-as-a-service platform.
Set up a cryptocurrency mining operation involving several ASIC miners as well as self built GPU mining installation. Built the full dashboarding required to monitor the mining operation, including the ability to switch the GPU miners from one cryptocurrency to the other on-the-fly. Maintained this installation until summer of 2019, when it was decommissioned.
Used technology: Bitcoin, blockchain, cryptocurrencies, cryptocurrency mining
Decos Minute
Software Architect
(April 2013 - September 2017)
Within a small startup (three people) within the Decos group responsible for the software architecture and lead development of Minute (iPad and Web app for meeting collaboration) - www.getminute.com.
I designed the technical foundation of this app, and guided the development. This was the first project for Decos leveraging cloud technologies (Microsoft Azure) as well as mobile apps (Objective-C, iOS), and later migrated to the first hybrid app (using Ionic framework). Both hybrid mobile and Azure are still technologies used widely within the company. My work was greenfielding these technologies and discovering them without prior knowledge within the company to found on.
Used technologies: Microsoft Azure, Objective-C, Ionic, C# .NET
Decos
Software Architect
(September 2010 - March 2013)
Responsible for the technical architecture of two generations of the Decos Customer Contact System, still in use today. Researching and proof-of-concept building for potential architectures, writing detailed architecture designs, and guiding the development team of ~10 software engineers to build and maintain the system. One of the first projects within Decos to adopt message bus based architectures, micro services, web socket technology, ORMs. First project to use agile development methodologies, which proved to be very succesful.
Used technologies: C# .NET, Silverlight, NServiceBus, SignalR, NHibernate, AngularJS
Decos
Team Manager
(July 2008 - September 2010)
Responsible for managing a team of Dutch and Indian engineers in building and maintaining integrations between Decos’s core product JOIN (then called “Decos Document - web edition”, later “Decos D5”) and dozens of external back- and front office systems in use in government, education and health care.
Used technologies: C# .NET, XML/XSLT, SQL SSIS
Decos
Software Developer
(July 2003 - July 2008)
Developer working on Decos Document - web edition (later Decos D5, later Decos JOIN) - a web-application for document- and case management in use in government, health care and education sector.
Used technologies: Visual Basic 6, C#.NET
Decos
Junior Software Developer
(July 1998 - July 2003)
Junior developer maintaining and building various small extensions to the predecessor of Decos Document - web edition called Decos Post (Clipper).
Used technologies: Clipper, Visual Basic 3-6
