Pieces of my work

For TokenForge GmbH and its client Chartered Investment & eSec, a registrar for Security Tokens, I wrote Smart Contracts and a corresponding d'App for the management and issuance of Security Tokens on the Avalanche Blockchain in accordance with the German Electronic Securities Act ("eWpG").

My tasks in detail:

• Development of the Smart Contracts in Solidity (ERC20 + ERC1155 for Permissions according to eWpG)
• Development of the d'App for the issuance of shares
• Development of the d'App for the registry law
• Development of the snapshots for the registry excerpt

More information:

• Announcement on Twitter (opens in a new tab)
• BaFin (opens in a new tab)
• Press Release (opens in a new tab)
• Contract Address (opens in a new tab)

Facing difficulties acquiring test-tokens due to drained faucets on various blockchains such as Goerli and Polygon, my team and I frequently encountered obstacles during product testing, development, and demonstration. To circumvent these challenges, we decided to create our own EVM blockchain using Avalanche SubNets, providing us with robust testnets to experiment with the deployment of SmartContracts, token interactions, and the minting of various token types, such as NFTs, SecurityTokens, and ReFi components.

Now we proudly manage our own chains, run our own faucet, operate our own block explorer via Blockscout, and, with immense gratitude to the open-source community, we even have our own SmartContract execution tool, which delivers a user experience surpassing that offered by Etherscan and its counterparts.

More information can be found here:

💥 Why And How We Built Our Own Blockchain for effortless Building, Testing and Token Abundance.

• Twitter (opens in a new tab)
• Article on LinkedIn (opens in a new tab)

Thanks to Avalanche SubNets and Blockscout we are running our own EVM.

For tokenforge and our client, Below2 Inc. (USA), I wrote the Smart Contracts for the tokenization of Carbon Credits, which includes the actual tokens, a vault contract for the retirement of the Carbon Credits, and receipt tokens that are automatically sent back as a receipt for the deposit of the CO2 tokens.

In addition, along with our Web3- and UI-team, we developed a d'App for management, the issuance of tokens, as well as for customer-side token retirement.

My tasks in detail:

• Development of the Smart Contracts in Solidity
• ERC20: Carbon Credits
• Custom: Vault Contract for the retirement of Carbon Credits
• ERC20 + ERC1155: Receipt Tokens
• ERC1155: Permissions for the issuance of the Carbon Credit Tokens
• Development of the dApp for the issuance of tokens
• Development of the dApp for the storage ("retirement") of Carbon Tokens

More information: https://below2.earth/ (opens in a new tab)

The underlying suite of SmartContracts, that we wrote for such usecases, can be found on GitHub (opens in a new tab).

tokenforge is a Berlin-based technology provider that offers its customers a software toolkit for asset tokenization, that offers the possibility to tokenize assets compliant with the law, fully digital and with no code.

For Tokenforge and its clients we developed an All-in-one toolkit for Security Token Issuance:

The Security Token Suite enables fast, legally compliant and secure issuance of bonds and digital securities:

• MiFiD II compliant underwriting process
• Fully automated token- and wallet generation
• Admin dashboard for efficient data- and issuance management
• eCommerce-like experience for investors
• Integration of KYC/AML, UBO and payment providers
• Stable and reliable token-minting experience
• Fully automated and scalable token issuance + transferability
• API First Approach (Launchpad-API | Chain-API)
• "Wallets as a Service" implementation
• additionally Integration of external Custody-Providers

My Tasks:

• Software Architecture (Microservices)
• Team-Lead Engineering at the beginning, followed by a typical CTO-Role
• Software Development on all levels
• Cryptography
• On-Chain-/Web3 development
• Backend engineering
• Setup Infrastructure with DevOps

As a member of a technical expert advisory consortium supporting Philips & Byrne, I had the privilege to support them specifically in the areas of Cryptography and Blockchain during a technical due diligence of a crypto-related company. My particular activities included:

• Code Reviews / Auditing
• Interviews with the CTO
• Developer interviews
• Architecture assessment

For TokenForge GmbH and its client Greenrock Energy (Austria & Germany), I developed Smart Contracts and a corresponding d'App for the management and issuance of Security Tokens on the Polygon Blockchain in accordance with the German Electronic Securities Act ("eWpG").

My tasks in detail:

• Development of the Smart Contracts in Solidity (ERC20 + ERC1155 for Permissions according to eWpG)
• Development of the d'App for the issuance of shares
• Development of the d'App for the registry law
• Development of the snapshots for the registry excerpt

Information about the Project:

• Press Release (opens in a new tab)
• Article in Börsen-Zeitung (opens in a new tab)

For tokenforge and its chain backend we developed Wallet As A Service: a scalable and secure set of wallet infrastructure APIs, enabling companies to create and deploy fully customizable onchain wallets to their end users. Companies can offer their users wallets directly in their apps with onboarding as simple as a username and password.

Technology stack:

• AWS KMS
• Go
• NestJS
• PostgreSQL
• VPN
• Cryptography
• Elliptic Curves
• Hierarchic Deterministic Wallets
• BIP-32, BIP-39, BIP-44

For tokenforge and our client, I developed Smart Contracts for the tokenization of GmbH shares, as well as for complex access permission models. In addition, I worked with our team of web specialists to develop a web app for managing all on-chain processes (d'App).

My tasks in detail:

• Development of Smart Contracts in Solidity
  • ERC20
  • ERC1410
  • Whitelisting
  • Factory Contracts
• Access Control Management for different governance roles
• Development of the web front-end for token "minting"
• Development of the web front-end for managing whitelists on the Smart Contract and for managing different permission roles.

For TokenForge GmbH and its clients, I continually developed Smart Contracts for various approaches revolving around NFT and utility tokens. In addition, I developed a centralized backend to make the management of on-chain processes accessible via a REST API (keyword Web 2.5).

My tasks in detail:

• Smart Contracts in Solidity based on:
  • ERC20
  • ERC721
  • ERC1155
• Tools for minting tokens
• Tools for managing metadata and files on IPFS
• Image manipulation for generative Art

For Chartered Investment Germany GmbH, Düsseldorf, Smart Contracts and necessary web applications were developed for a digital security on the Ethereum and Avalanche Blockchains, in accordance with the Electronic Securities Register Act.

The collaboration took place in close coordination with the law firm Lindenpartners, Berlin, to align with the requirements of BaFin and to consider all regulatory aspects.

Tasks & Activities:

• Conceptual collaboration regarding the interpretation of eWpG in terms of technological possibilities and constraints in the Ethereum protocol Development of Smart Contracts
  • ERC20
  • ERC1410
  • Whitelisting
  • Factory Contracts
• Access Control Management for different governance roles
• Development of the web front-end for token "minting"
• Development of the web front-end for managing the whitelists on the Smart Contract and for managing different administrative roles
• Development of a backend for the registry management and determination of token balances per investor's wallet
• Close cooperation with lawyers in favor of regulatory guidelines

Press-Release:

• BTC-Echo (opens in a new tab)
• Verified Contract at Etherscan (opens in a new tab)

For the clients of TokenForge GmbH from the financial market, we are developing a product suite with a team of software developers, UX specialists, and lawyers, which allows issuers to emit and manage digital assets at the blockchain level. This includes:

• Asset Management
• Investor Management
• Investor Dashboard
• Fully automated handling of tokenization (Minting, Transfer, Burn)
• Registry extracts
• Payment options including Stripe, PayPal and cryptocurrencies
• Invoice-Management
• Automated dividend and interest payouts
• Cryptocurrency processing
• Minting Studio for issuing and distributing tokens

My tasks:

• Software Architecture
• Leading the Engineering team incl. DevOps
• Backend Development
• Development of On-Chain components (SmartContracts, dApps-Connectivity, RPC-APIs)

As a member of a technical expert advisory consortium supporting Philips & Byrne, I had the privilege to support them specifically in the areas of FinTech and Blockchain during a technical due diligence of a well-known cryptocurrency exchange. My particular activities included:

• Code Reviews / Auditing
• Interviews with the CTO and CEO
• Developer interviews
• Architecture assessment
• Security assessment around wallet management and blockchain interaction

As a member of a technical expert advisory consortium supporting Philips & Byrne, I had the privilege to support them specifically in the areas of Cryptography and Blockchain during a technical due diligence of a FinTech building with Hyperledger.

My particular activities included:

• Code Reviews / Auditing
• Interviews with the CTO
• Developer interviews
• Assessment regarding HyperLedger/Swiss Trust Chain and their Chain Code

As a joint project with our client weeCommerce AG, we created a Payment Gateway that can handle the complete payment processing within the framework of a WhiteLabel Banking System. The following features are provided within a REST API:

• Account opening for both private and business customers (Europe-wide)
• KYC (Know Your Customer)
• UBO (Ultimate Beneficiary Owner Check)
• Deposits of credit into internal eMoney-based wallets
• Withdrawals of credit to bank accounts via IBAN
• Transactions between wallets
• Bulk transactions between different wallets as individual transactions
• Credit Card Payments including 3DSecure

My tasks:

• Development of the entire software architecture and the final technology stack
• Team Building
• Technical Product Owner
• Development of the banking engine and the REST-API in Go
• Team coordination in collaboration with other developers
• Planning and coordination of peripherals (dashboards, monitoring, recovery)

Technology-Stack:

• Go (Backend, Services, REST-API)
• nats.io (message bus)
• ProtoBuf (data layer / protocol)
• PostgreSQL
• Prometheus
• Grafana
• GrayLog / ElasticSearch
• Traeffik
• KeyCloak
• Kubernetes
• ReactJS for Admin-Dashboard

During the development of our STO launchpad (see below), the so-called snapshotting of the EVM blockchain for dividend or interest payments turned out to be a by-product that we will separate out and market as a separate product in the future.

My tasks:

• Programmatic implementation of "snapshotting" for requested tokens on the Ethereum blockchain in general.
• Database scheme for time series and big data based on TimescaleDB and PostgreSQL
• Writing PostgreSQL Extensions for this kind of data
• History of token transfers
• REST API
• Own payment system for Bitcoin and Ether payments
• Connections to other banking interfaces for automatic payment of dividends
• Admin dashboard for managing customer data and payments, invoices, etc.

Blockchain Research and Development Project in the Independent Automotive Aftermarket (NDA protected).

My tasks:

• Consulting around Smart Contracts on the Ethereum Blockchain.
• Development of smart contracts with Solidity
• Backend + REST API for OnChain operations.
• Gas Fee simulation
• Optimization of smart contracts in terms of memory consumption and fees
• Interaction with the SmartContracts via Web3.js into an existing Angular application

Palmtrip GmbH would like to issue a Security Token with BaFin-Approval. The Security Token will be a regulated security with its own WKN/ISIN. Via the token, dividends will be distributed annually to the token holders via snapshot. Regulatory requirements on the part of BaFin require a special design of the token contracts with regard to transferability. So-called Oracle techniques are used here to link the on-chain world with the off-chain world.

My tasks:

• Test-driven development of SmartContracts based on the umbrella standard for security tokens according to ERC 1411 (formerly ERC 1400)
• Token Sale & Distribution dApp
• Consulting around token design in coordination with the lawyers involved regarding legal and technical feasibility
• Distribution platform for token acquisition, investor management and dividend payments
• Integration of Solarisbank Banking API & Digital Assets API
• ERC-20 backward compatible
• Whitelisting for token transfer
• ERC-1594: Core Security Token Standard
• ERC-1410: Partially Fungible Tokens
• ERC-1643: Document Management Standard
• ERC-1644: Controller Token Operation Standard
• Use of Oracles for injecting off-chain KYC into Token Transfers
• Integrated crypto-payments
• Fiat payments via external payment providers
• Uploads of legal documents to IPFS and deposit of hashes in the SmartContracts per token purchase as part of a partitioning process

Development and technical preparation of Iron Eagle Capital GmbH's ICO for the in-house Nuco cloud and the NCDT token.

• URL: https://nuco.cloud/ (opens in a new tab)
• Smart Contracts: https://github.com/nucocloud/ncd-token (opens in a new tab)
• Etherscan Mainnet: https://etherscan.io/token/0xe0c8b298db4cffe05d1bea0bb1ba414522b33c1b (opens in a new tab)

My tasks:

• Training and ongoing advice to the founding team on blockchain-related topics and on the technicalities of an ICO.

• Teambuilding legal framework (external via Lindenpartners/Berlin)

• Technological whitepaper support

• Design of the token economy

• Affiliate program / bonus program with different levels

• Distribution platform for token acquisition and investor management

• Integrated crypto-payments

• KYC/AML via Fractals

• Fiat-Payment via Micropayment

Founded in 2016, the startup YAIR secures the access and value of digital artworks through blockchain technology, making digital art accessible and tradable for the art market.

My activities:

• Ongoing technical consulting around Blockchain, SmartContracts and the upcoming STO (Security Token Offering).

• Project planning with the team and investors

• Development of the SmartContracts (ERC-721, ERC-20, ERC-1400), backend, marketplace and mobile apps with Flutter (cross-platform iOS & Android).

• Leading the development of the token sale platform:

  • User management
  • Artwork management
  • Affiliate program / bonus program with different levels
  • Token Sale, payment & distribution
  • Payment-Methods: ETH, BTC, Aeternity-Token

• Planning and leading the development of the digital art trading platform

• VR app with display connectors to external devices such as Samsung Frame and other VR headsets.

Technology Stack:

• Backend:
  • Symfony, Sylius, Doctrine, API Platform, Swagger
  • Docker, Kubernetes
• On-chain:
  • Ethereum
  • Aeternity-Blockchain
  • IPFS
  • StorJ
• Mobile:
  • Flutter / Dart
  • ReactNative (MVP, migrated to Flutter)
  • BLOC, Reactive Programming
  • Unity3D
  • Vuforia
  • ChromeCast
• AWS:
  • EC2
  • S3
  • Cloudfront

Programming languages:

• Dart
• Solidity
• PHP
• Sophia
• Objective-C
• Java
• Swift
• C++

Analysis and auditing of the software structure and quality of a startup in the field of online travel services for the Southeast Asian region based in Kuala Lumpur / Malaysia.

Technology Stack:

• Code base & packager:
  • React, ES6/ES7, JSX, Webpack, Babel
• Data-Layer:
  • graphQL, relay
• Frontend:
  • Express, Materialize, PostCSS
• Authentication:
  • auth0.com

For this German eCommerce startup with a code base that was over 10 years old, a step-by-step decoupling of the legacy monolith into a complete separation of frontend, backend, database layer and other services (analytics, API connections, client connection) was carried out.

The focus here was on the ongoing separation of individual software components into the new architecture and the encapsulation of fragile, security-relevant legacy elements in secure containers to enable a seamless, gradual transition of the legacy architecture into the new architecture.

Similarly, an optimization of the product search function was implemented using ElasticSearch.

Technology-Stack:

• PHP
• MySQL
• Magento
• Wordpress
• ElasticSearch
• Symfony
• Docker
• Swagger
• Behat
• Logstash & Kibana

At the beginning of 2018, Cleyond AG, formerly CleanCore AG, decided to conduct a capital raising in the form of issuing its own utility token based on ERC-20 to be used for Crowd Investing.

My activities:

• Training and ongoing advice to the board regarding blockchain-related topics and about the technicalities of an ICO.
• Teambuilding legal framework (external)
• Technological whitepaper support
• Design of the token economics _ Support in the management of crypto wallets (HD wallet per blockchain)
• Development of the token sale platform with the following requirements:
• Whitelisting period
• Affiliate program / bonus program with different levels
• Token Sale and distribution
• Payment methods: ETH, BTC, Fiat
• SmartContracts:
  • Token Contract (ERC-20)
  • Vesting-Contract
• KYC/AML via IDNow

As part of a possible realignment of the company's in-game currency with a possible blockchain-based digital currency, I conducted a full-day workshop focusing on the following:

• How a blockchain works based on Bitcoin and Ethereum.
• Introduction to cryptocurrencies
• Possibilities of tokens as a means of financing/payment/security
• Token economics definition based on the present use case
• Phases of an ICO, necessary steps
• Current legal basis based on a memo from my legal department

Ongoing consulting and development of a mobile app via ReactNative since January 2018 until end of 2019.

For Moving Elements GmbH, I developed the embedding of Unity3D/Vuforia applications into a ReactNative app. Furthermore, I conducted a 1-week team training on the ReactNative framework and facilitated and continuously accompanied the "transformation" of the previous team from web developers to ReactNative developers.

Technology / Programming Languages:

• ReactNative
• Javascript
• Objective-C
• Objective-C++
• C++
• Ansi-C
• C#/C-Sharp
• Swift
• Unity3D
• Vuforia

Official description text of the app:

As the first 100% independently programmed messenger according to German data protection law, Cooblr takes the data of its communication participants seriously. In addition to the normal chat function, advanced features like file sending, team creation and an internal event planner make the app a real asset in team communication!

The Messenger App had group chats, audio chats and video chats. Files could be transferred and organized. An offline function allowed chatting and sending files even without any Internet connection via message queues. As soon as the smartphone got an internet connection again, the cached messages has been sent automatically.

For this app, I assembled a team of backend and frontend developers and actively led the development, taking an active role in leading and contributing on all fronts.

Technology / Programming Languages:

Backend:

• Loopback (NodeJS)
• Docker
• Google App Engine
• AWS EC2, S3, Cloudfront

Frontend:

• React Native, ES6/ES7
• Redux, Redux Saga, React-Router-Flux
• Sqlite3, React-Native-Sqlite-Storage
• API-Calls to the Backend with caching layer
• Objective-C and Java for Encryption, Audio- und Video-Support

During that time, I contributed heavily into the React Native driven eco-system.

I was developing the iOS and Android app for the German-Italian startup SuperCommuter GmbH. The app features a very sophisticated design and an equally sophisticated user experience, which definitely posed a big challenge for the development with React Native and required some research work as well as ingenuity.

Rest API's are consumed and detailed, extensive travel booking routes are offered up to booking via app with the common payment systems such as credit card, Paypal and direct debit.

Technology:

• React Native, ECMAScript 2016
• Redux, Redux Saga, React-Router-Flux
• Sqlite3
• React-Native-Sqlite-Storage
• API-Calls to a Backend

The Energetix GmbH & Co. KG with 80 employees and headquarters in Bingen am Rhein produces and sells jewelry in 17 countries with an annual turnover of 80 million euros (according to the website). I developed a multilingual app for the sales department of this company, with which product data can be searched, viewed and ordered at the customer's location.

For this app I developed, among other things, a Redux-based middleware for the flexible support of multilingualism to currently support 5 languages, between which can be switched at any time.

Within the app, item data is loaded and cached from a server depending on the language and currency set, and then both the items and item variants can be searched. The app has been optimized for offline use at the customer's site without mobile connection.

Technology:

• React Native, ECMAScript 2016
• Redux, Redux Sagas, React-Router-Flux
• Multilingualität (5 languages)
• Sqlite3, React-Native-Sqlite-Storage
• API-Calls to Backend with caching layer
• PHP + Slim Framework + MySQL for REST API/Backend

As Co-Founder and CTO for the German-American startup Zizzle eLearning Inc. based in Salt Lake City (USA), I lead the development of the backend as well as the iOS and Android app together with 3 other app developers in the first half of 2016.

React Native was chosen for development with the goal of creating a broad codebase that served both iOS and Android across platforms. Components that were missing in React Native or did not produce the desired result, I implemented natively in Objective-C (for iOS) and Java (for Android). Partially, we published our results under an open source license on Github for the libraries we used.

We've been the very first React Native app that has been released in the AppStores, according to Facebooks Developer Relations Manager.

Technology:

• React Native, ECMAScript 2016
• Redux, Redux Sagas, React-Router-Flux
• Objective-C
• Java
• InApp-Purchase / Subscriptions
• PHP 7
• Symfony / Sylius
• Sqlite3 (client), MySql (server)
• Unicode for support of Chinese characters
• AWS, EC2, Cloudfront

My work for this project consisted on the one hand in the PHP-based backend (REST API, MySQL database, chat protocol, geolocation based services, message queues) and on the other hand in the implementation of the native iOS variant of the Chat App, built with Objective-C, REST client, LocalStorage, animations, radar search, chat client and a very sophisticated design.

Technology:

• Objective-C, Kiwi
• ReactiveCocoa, AFNetworking, FMDatabase
• PHP 5.6, PHPUnit
• MySQL 5.6, Liquibase
• Slim (PHP-Framework)
• AWS S3, Cloudfront
• Cloudinary

The focus of my work as Teamlead Of Engineering in this project was the conception of the software architecture (backend, mobile) as well as the implementation of the same in the context of the technical team management.

Team size: 3 developers, 3 product managers, one web- and app designer.

My focus was on the app development for iOS as well as the REST API on the backend side.

In detail: REST API's, native mobile apps (iOS, partly Android), frontend and administration interface as well as various backend tools (native app, APIs & web).

Technology:

• Objective-C
• Reactive-Cocoa, AFNetworking
• PHP 5.5
• MySQL (Percona) 5.6
• ElasticSearch
• Symfony 2, PHPUnit, Bootstrap
• Node, npm, Bower, Composer, Grunt
• Vagrant/Puppet
• Javascript
• Titanium AppCelerator
• Kiwi (TTD for native iOS Apps)
• Cloudinary

Here I accompanied the complete refactoring of the Yatego marketplace towards a performant, scalable, modern software architecture.

Main focus: REST API's, high performance databases and business logic, replication, data migration, ElasticSearch connectivity for fast searches.

Technology:

• PHP 5.5, JavaScript
• MySQL (Percona) 5.6, Liquibase
• ElasticSearch
• Symfony 2, PHPUnit, Bootstrap, Kiwi
• Node, npm, Bower, Composer, Grunt
• Vagrant/Puppet

Web2Print: Development of a browser-based WYSIWYG designer for creating print products in the browser (business cards, stationery, flyers, brochures, catalogs, etc.). Main feature: pure Javascript, HTML 5, CSS 3 - no Flash, no Java required. Generation of print-ready PDFs with personalization. This web editor for print products is marketed as part of an online store solution of the integrated industry solution EFI LECTOR (MIS). Also: Modernization of legacy code (PHP, outdated store system).

Technology:

• PHP 5.3, ZendFramework
• Coffeescript, Javascript, knockoutJS, kineticJS
• MySql 5.5
• PDF-Erzeugung und –Parsen, TCPDF
• Bootstrap
• PhantomJS

Foundation of the company with a partner and some physicians: independent conception as well as development of a health portal for the collection of health values and numerous evaluations as well as physician reports.

The architecture of this portal was designed and mainly implemented by me:

• Development of the web application: backend, frontend, data model
• Browser-based frontend testing with Selenium-Grid and Python
• Development of the community solution (timeline, feeds, comments, circles, likes, uploads...)
• Development of the health card (QRCode generation, QR code scanning via smartphone, cryptopgraphy, PDF generation for plastic card printing after survey by interactive online questionnaire, print route)

Technology:

• PHP 5.4, PHPUnit, Zend Framework
• MySql 5.1
• Objective-C, Python, Java
• Coffeescript, Javascript, knockoutjs, phantomJS
• Selenium, AWS S3, Cloudfront

Software development of the following browser and intranet based software solutions for insurers:

Amakura-PK: administration solution for pension funds
Amakura BV: member administration for professional pension funds
Amakura LV: administration platform for life insurers

Technology:

• ASP.NET / C#
• Coffeescript, Javascript, jQuery, knockoutJS
• TDD Introduction,
• OR-Mapper
• MS SQL Server
• Database Performance Optimization

Software development of the online auction platform (realtime), development of the buyer control panel, iPayment integration (online payment, credit cards), SAP interface.

Technology:

• PHP 4/PHP 5
• MySQL
• Javascript / jQuery
• WebServices (SOAP, REST)

Software Development of numerous modules for the Windows-based industry solution (MIS) LECTOR Druck (eCommerce, accounting, order processing, data imports/exports, interfaces to third-party providers, production data acquisition, capacity planning).

Main focus:

• System libraries (Windows, C++)
• Interactive CAD/CAM solution for online design/calculation of printed sheets
• FIBU interfaces (SAP, IBM, Navision etc.)

Client: Klinikum Frankfurt (Oder) and Klinikum Straußberg

Freelance development of a software for automated, strategic planning of duty schedules for clinics as well as employee management.

Technology:

• Turbo Pascal with Objects
• Assembler
• Delphi
• Win32