Owner and sole developer.Native iOS and macOS development. Data engineering & data analysis.Available for freelancing onsite in the Netherlands and around Europe, or remote.I can help with GTM (go to market) solutions, from product ideation to development, to launch strategies.Recent work with data and data engineering:Financial analysis in financial markets:- Time series return predictions.- Cross-sectional return predictions.- An options strategy for trading equity options (straddles) over earnings announcements. Long straddle ahead of earnings, and reverting short just before - an effect Euan Sinclair has written about in his books, and which is covered in research papers.- Analysis of seasonal returns.- A futures basis arbitrage. Analyze the persistence of the funding rate for perpetual futures, and design a trading strategy.Data engineering pipelines for data ingestion from exchanges. Preparing data for analysis: cleaning, storing, enriching it.Python scripts to monitor real-time prices of instruments across exchanges, and send notifications for wide spreads.Built a notifications system to send text messages (Telegram) for notable events occurring on trading exchanges.Older works:My portfolio of apps and client work is listed on the website (http://codexbit.com).

Released KYC (Know Your Customer) features like face scan, document validation for the mobile banking app.Responsible for improving the architecture of the app (MVVM with flow coordinators) by using functional reactive programming, and patterns like unidirectional data flow and immutable state.Made improvements to the components based design of the app on multiple levels: achieved better separation of concerns, separation of business logic, improved testing coverage, and improved reusability of the components greatly.Created proof of concepts to demonstrate / test the potential of features to be added to the app.Held knowledge sharing sessions in the team to drive adoption and understanding of technical subjects.Collaborated across teams to clarify requirements and ensure stakeholders understand the impact of the business features.The app uses functional reactive programming patterns (ReactiveKit, Combine) and we adopted SwiftUI.CI tools, automation, Swift, SwiftUI, functional reactive programming, Combine, ReactiveKit

Developed new features for the TNT app in the AppStore.Introduced functional reactive programming (RxSwift) and functional programming patterns, with an MVVM-C architecture in the TNT app. Achieved a high level of testability for the app, implementing unit tests for business logic, and integration tests for ViewModels). Used UI Tests for multi screen critical business flows tests, and for generating AppStore screenshots.Used CI/CD (Fastlane & Bitrise) to streamline delivery workflow: generate AppStore screenshots in multiple languages, create testing builds, make releases to the AppStore, etc.Held knowledge sharing sessions and played an advisory role to the developers in Dallas for improving the FedEx app architecture - as part of the FedEx integration.Conducted job interviews for specialist positions.

A successful iOS weather app. I was the only developer of the app from its launch in 2013 until 2018. Worked in a freelance then partnership agreement. The app was featured by Apple multiple times, and was a top paying app in 23 countries. It’s highly regarded, reviewed by iMore, 9to5Mac, MacStories, and with a dedicated user following.I significantly reduced the operating costs associated with the weather data provider by creating cloud based caching solution.See review links and testimonials: weatherlineapp.com/press/

I helped launch the first version of the TomTom Go mobile navigation app for iOS as part of the mobile team at TomTom. The app was a huge success.Work involved interoperating with C++ for the core map unit, and we built a highly modular design based on the MVVM pattern.

iOS / OS X development.

Responsible for continued development of R&D Media’s various advertising and marketing platforms.

R&D developer responsible for prototyping a price notification concept for a travel industry partner, and analysis and architecture design for concrete client implementation, using software development best practices in terms of design patterns and SOA practices to achieve loosely coupled system integration.

Involved in all aspects of the software lifecycle from analysis, design, development, and testing of a variety of solutions addressing Albumprinter’s photo book business: APIs, backoffice systems, cloud computing solutions.Make use of software development best practices: design patters, SOA (service oriented architecture), domain driven design.

Design and implementation of solutions for managing public procurement notices to TED - the Official European Public Procurement office.

Software developer at Flame (the technical division of TotalStayGroup - www.totalstaygroup.com).Net software architecture, design and development position, with focus mostly towards ASP.NET web applications, web servies, middle tiers.Responsible for enhancements and development of additional features for the online travel solutions www.hotelpronto.com and www.exclusivelyhotels.com, and integration with other systems for a full fledged automated business process.

Responsible for creating a suite of privacy protection, cryptography and computer management applications. Project leading, architecture, design and development of CME (Content Management Engine) solutions, web portals and web applications for different clients.