Lucas van Dongen, Developer in Rotterdam, Netherlands
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Lucas van Dongen

Verified Expert  in Engineering

iOS Developer

Rotterdam, Netherlands
Toptal Member Since
December 8, 2015

Lucas is a Dutch developer that specializes in iOS development. He loves to create software solutions in close partnership with his customers, and he always polishes his work until he finishes with a perfect product. Lucas has spent the past few years working at Before that, he did a lot of contractor roles for mainly US-based clients, ensuring to keep up with new technologies since mobile development changes so rapidly every year.

Swift, SwiftUI, Combine, GraphQL, Software Design, Agile, Dependency Injection...
Cocoa, MacOS, Swift, Combine, AppKit, AppleScript, Agile, APIs, Mobile
OS X, iOS, Agile Software Development, WebRTC, Swift, Objective-C, UIKit...




Preferred Environment

Git, Xcode, MacOS, Swift, iOS

The most amazing...

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

Work Experience

Senior iOS Software Engineer I

2021 - PRESENT
  • Created the insurance module that sells travel and cancellation insurance to hundreds of clients daily.
  • Developed a vision document for creating a solution for Dependency-Track that will be implemented and used throughout the whole app once completed.
  • Increased sales with a considerable margin (over 100%) by consistently running experiments (currently over 30) that might reduce friction to buy or create more trust in our insurance products.
  • Tracked and monitored the health of our experiments and user experience through various tools.
Technologies: Swift, SwiftUI, Combine, GraphQL, Software Design, Agile, Dependency Injection, Architecture

Lead macOS Developer

2020 - PRESENT
  • Created a macOS application that monitors the activities the user performs in applications or websites on their computer to quickly and privately help the user generate an overview of how much they worked on what project.
  • Created a Safari extension that can intelligently detect what a user is doing in web applications, like what client the user works for in a finance portal or what client's email they are reading on Gmail.
  • Implemented a complete workflow for developers or maintainers to deploy the app or the Safari extension completely automatedly.
Technologies: Cocoa, MacOS, Swift, Combine, AppKit, AppleScript, Agile, APIs, Mobile

Senior Lead Developer

2011 - PRESENT
  • Developed an application that used WebRTC to video call between various different platforms.
  • Worked at Steady App, building their iOS client. Was the most productive member of all front-end developers working there.
  • 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 Automotive, the importer of Volkswagen and related car brands in the Netherlands.
Technologies: OS X, iOS, Agile Software Development, WebRTC, Swift, Objective-C, UIKit, SwiftUI, Maps, SDKs, MapKit, MapKit API, Agile, Technical Writing, Documentation, Kotlin, WebView, Mobile Development, iOS SDK, iOS Native Libraries

Senior iOS Developer

2020 - 2020
Royal KPN
  • Supported the development team as a senior iOS developer to help solve a complex issue for a project whose details I cannot disclose.
  • Enabled the development team to work independently after successfully solving the issue.
  • Wore different hats to investigate and resolve the complex issue, as many layers were involved to make it work, including networking problems.
Technologies: Swift, Python, Dart, Video Streaming, Digital Rights Management (DRM), SDKs, Agile, Kotlin

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, Agile

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, Agile

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, Agile

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, Agile, Kotlin, WebView

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, Agile

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, Agile


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, Agile


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#


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: Active Server Pages (ASP), ASP.NET, C# Project
The top application in the travel section of the App Store and worldwide market leader for accommodations. Used by millions of people globally every day. I worked on a very large-scale project in terms of developers, lines of code (1.5 million), tooling, release schedule (twice per week), amount of daily users, and transactions.

I used SwiftUI and Swift with MVVM in our own module and interacted with older implementations in UIKit and Objective-C. A notable achievement is I created the roadmap for modernizing the dependency injection implementation that is being rolled out in the coming years. There was a heavy accent on Clean Code and designing complex interactions with the back end while cleaning up older code.

Steady App
Steady is an app geared toward finding jobs in the gig economy in the US. The quality standards were very high—with over a million concurrent users and frequent releases. I worked in a team of iOS and Android developers and managed to be the top contributor in terms of velocity.

The project was a model–view–viewmodel using Reactive paradigms through ReactiveKit, comparable to RxSwift and Combine.


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 who have to declare their worked hours while it also helps register them far more accurately.

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 deployment 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. It has beautiful hand-rendered animations and has been in the App Store for almost a decade. It's the oldest piece of software I still support.

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 restock items quickly.

The project involved refactoring all logic and data handling as much as possible to 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 saved much time and allowed the team to keep a shared codebase. Getting the scanner to work via a bridge was quite challenging and very interesting.
2007 - 2012

Bachelor's Degree in Computer Engineering

Fontys University of Applied Sciences - Eindhoven


CocoaPods, WebRTC, iOS Native Libraries, MapKit API, Alamofire


Xcode, Microsoft Visual Studio, Interface Builder, Git, JetBrains, Visual Studio, AppCode, Fastlane, WebView, GitLab CI/CD


SwiftUI, ASP.NET MVC 5, .NET, ASP.NET, Cocoa, iOS SDK, Combine, Catalyst, ASP.NET Web API, MapKit, Django, Phoenix, Windows Presentation Foundation (WPF), AppKit, UIKit, ReactiveKit


SQL, Objective-C, Swift, C#, Active Server Pages (ASP), C++, HTML5, CSS, Elixir, Python, PHP, JavaScript, GraphQL, AppleScript, Dart, Swift 5, Swift 4, C, Kotlin


Agile Software Development, Model View ViewModel (MVVM), Model View Controller (MVC), Agile, Mobile Development, Scrum, Reactive Programming, Continuous Integration (CI), Dependency Injection, Unit Testing


iOS, Mobile, Xamarin, MacOS, Android, OS X, Web, Software Design Patterns


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

Industry Expertise



iPadOS, Code Architecture, Mobile Architecture, Video Chat, Messaging, SDKs, Documentation, Architecture, Education, Streaming, Maps, Technical Writing, APIs, Safari Extensions, Leadership, Finance, TCP/IP, Software Design, Video Streaming, Digital Rights Management (DRM), Xamarin.Mac, CI/CD Pipelines

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