Lucas van Dongen, iOS Developer in Utrecht, Netherlands
Lucas van Dongen

iOS Developer in Utrecht, Netherlands

Member since December 8, 2015
Lucas is a Dutch developer that specializes in iOS development. Lucas loves to create software solutions in close partnership with his customers, and he always polishes his work until he finishes with a perfect product. He has spent the past few years working remotely for US-based clients, making sure to keep up with new technologies since mobile development changes so rapidly every year.
Lucas is now available for hire


  • Freelance
    Xamarin, ASP.NET, OS X, iOS
  • GemVision
    Model View Viewmodel (MVVM), Xcode, Web, Android, iOS, Swift, WebRTC
  • ClockAssist
    MacOS, Cocoa, Model View Viewmodel (MVVM), Swift, Xcode, iOS



Utrecht, Netherlands



Preferred Environment

Git, Visual Studio, JetBrains, Xcode, MacOS

The most amazing...

...thing I've developed is a WebRTC solution that works between iOS, Android, web, and smart glasses.


  • Developer

    2011 - PRESENT
    • Developed an application that used WebRTC to video call between various different platforms.
    • Worked at Steady App, building their iOS client.
    • Developed parts of the iOS and Xcode course on Pluralsight.
    • Wrote an ASP.NET MVC-based application for a distributor of phone parts in the Netherlands.
    • Developed an OS X project with Xamarin for pharmacies.
    • Created various iOS, Android, and hybrid solutions for PON Automobiles, the importer of Volkswagen and related car brands in the Netherlands.
    Technologies: Xamarin, ASP.NET, OS X, iOS
  • iOS Developer

    2019 - 2020
    • Created a WebRTC based real-time communications application from scratch.
    • Made it work together with the already existing web, smart glass, and Android clients.
    • Improved efficiencies in development processes.
    • Managed one other iOS developer.
    • Dealt with a lot of concurrency issues that arise from complex websocket implementations and WebRTC.
    Technologies: Model View Viewmodel (MVVM), Xcode, Web, Android, iOS, Swift, WebRTC
  • Lead iOS Developer

    2019 - 2020
    • Worked on determining the features for the mobile client and the UX.
    • Built the iOS client from scratch using Swift.
    • Delivered the MVP in just 15 days of working.
    • Worked on the macOS client.
    • Managed to improve efficiency to less than 1% of one CPU core.
    Technologies: MacOS, Cocoa, Model View Viewmodel (MVVM), Swift, Xcode, iOS
  • Senior iOS Developer

    2018 - 2019
    Steady App (via Toptal)
    • Delivered new features quickly and accurately.
    • Restructured the authentication part of the application.
    • Improved loading speeds using Reactive techniques.
    • Restructured dependency injections.
    • Improved the way designers communicated their designs to developers and communication in general.
    Technologies: ASP.NET, C#, Reactive Programming, Model View Viewmodel (MVVM), Xcode, Git, Swift
  • Team Lead and iOS Developer

    2018 - 2018 (via Toptal)
    • Created a HQ Trivia-like game from scratch.
    • Built the initial MVP myself, including the Elixir websocket server and Python web views.
    • Built a team around me once the MVP attracted funding existing of Python developers and an Android developer.
    • Worked on streaming video and voting at scale.
    • Contributed key decisions on what features we liked for the app and how they would work.
    Technologies: JavaScript, HTML5, Django, Python, iOS, Phoenix, Elixir
  • iOS Developer

    2017 - 2017
    Feldspar Studios (via Toptal)
    • Created the navigation structure using a router pattern.
    • Implemented the whole onboarding and login experience.
    • Implemented live voice transformation.
    • Helped improve the performance of the recording and playback screens.
    • Implemented push notifications.
    Technologies: C++, Swift
  • RokaCom iOS Developer

    2016 - 2017
    RokaCom (via Toptal)
    • Maintained a large secure VoIP and chat application written in Objective-C.
    • Refactored and improved the legacy code towards something that works reliably, is user-friendly, and is much more maintainable.
    • Added an onboarding experience including designs for icons so users would feel less intimidated giving the application rights to use the camera, microphone, and send push notifications.
    • Automated the build and snapshot process using fastlane and Jenkins.
    • Made the application support multi-user scenarios instead of only 1:1 communication.
    • Implemented the API calls in Swift leaving a good foundation for the future.
    • Pivoted the product to enterprise users.
    Technologies: Swift, Objective-C, iOS
  • Developer

    2012 - 2015
    Velocity Partners
    • Updated the AXS iOS application to version 2.0 and maintained the application afterward.
    • Maintained the Getty Images website and related brands (ThinkStock, for example) in ASP.NET.
    • Interviewed and mentored iOS candidates for the company.
    • Made frequent presentations about iOS development.
    • Prepared coding tests and questionnaires for iOS candidates.
    Technologies: C#, ASP.NET, iOS
  • Developer

    2012 - 2012
    • Worked on a custom application to aid the whole workflow of intake to aftercare for cancer patients in a hospital called Cure.
    • Researched the viability of offshoring the maintenance of the application.
    • Guided releases of Cure.
    • Automated the development, testing, staging, and live workflow for releases.
    • Maintained an application that tracks the health of livestock for Merck Animal Health.
    Technologies: Windows Presentation Foundation (WPF), C#
  • Developer

    2007 - 2011
    Itelligence Benelux
    • Maintained and updated an application for a large insurance company called IAK.
    • Created an enrollment site for the Maastricht School of Management.
    • Designed a management solution for time tracking.
    • Maintained the website for the largest air ticket company in the Netherlands in ASP.NET (
    • Created an insurance module for
    • Developed a CV portal for Welten that allowed recruiters to send tailor-made CVs to potential candidates in PDF.
    Technologies: ASP, ASP.NET, C#


  • Steady App

    Steady is an app geared towards finding jobs in the gig economy in the United States. With more than a million concurrent users and frequent releases the standards on quality were very high.

  • ClockAssist

    ClockAssist is a suite of applications where a desktop client that tracks your activities, a web client and mobile clients allow you to automatically register all your activities during the day like sending emails, making bills, editing documents, or having phone calls.

    This saves valuable time for professionals like lawyers, accountants, or software developers that have to declare their worked hours while it also helps registering them far more accurately.

  • Duolingo

    I've worked as a contractor for Duolingo (a language training application) through Toptal. Duolingo has millions of users, supports many languages, and has up to a dozen A/B experiments running at any time. Any step of the development, build, and deployments process that could be automated was automated.

  • Ovo Timer for iOS

    Ovo Timer is a beautiful, quick, and easy-to-use timer application for iOS devices.

  • Mediq Medeco Scanmodule for OS X

    This application is an OS X conversion of the Windows Scanmodule for Mediq Medeco that can be used with a barcode scanner and allows pharmacies to quickly restock items.

    The project involved refactoring all logic and data handling as much as possible to a separate the "core" project and get as much reuse as possible when integrating the core into the OS X version. This version was based on Xamarin.

    Xamarin really saved a lot of time and allowed the team to keep a shared codebase. Getting the scanner to work via a bridge was quite a challenge and very interesting to do.

  • Working With Static Patterns: A Swift MVVM Tutorial (Publication)
    Real-time data-driven apps create new challenges in the way we structure our programs, especially on mobile. In this article, Toptal Freelance iOS Developer Lucas van Dongen implements an iOS chat app, comparing the classic MVC approach with a static immutable MVVM pattern.


  • Languages

    SQL, Objective-C, Swift, C#, C++, HTML5, CSS, Elixir, Python, PHP, JavaScript
  • Frameworks

    ASP.NET MVC 5, .NET, ASP.NET, Cocoa, SwiftUI, Catalyst, ASP.NET Web API, ASP, Django, Phoenix, Windows Presentation Foundation (WPF)
  • Libraries/APIs

    CocoaPods, WebRTC, Alamofire
  • Tools

    Xcode, Microsoft Visual Studio, Interface Builder, Git, JetBrains, Visual Studio, AppCode, Fastlane
  • Paradigms

    Agile Software Development, Model View Viewmodel (MVVM), Model View Controller (MVC), Scrum, Reactive Programming, Continuous Integration (CI)
  • Platforms

    iOS, Xamarin, MacOS, Android, OS X, Web
  • Storage

    Relational Databases, Microsoft SQL Server, MySQL, PostgreSQL
  • Other

    iPadOS, Code Architecture, Mobile Architecture, Video Chat, Messaging, Combine, Architecture, Education, Streaming, Leadership, Finance
  • Industry Expertise



  • Bachelor's Degree in Computer Engineering
    2007 - 2012
    Fontys University - Eindhoven

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