Vojtech Vrbka, Developer in London, United Kingdom
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Vojtech Vrbka

Verified Expert  in Engineering

Software Developer

London, United Kingdom
Toptal Member Since
August 11, 2019

Vojtech is a London-based senior Swift contract developer with a master's degree in computer science and ten years of experience developing successful iOS apps for startups and established organizations. He works well in small and big teams, with more than 30 iOS developers supporting apps with millions of users.


Swift, SDKs, Frameworks, Custom Keyboards, Functional Reactive Programming...
Babylon Health
Coded UI Tests, Unit, Redux, ReactiveSwift, Swift
Optimizely, Firebase, Continuous Integration (CI), Coded UI Tests, Unit, Swift




Preferred Environment


The most amazing...

...app I've developed was Velocity, which I scaled from 0 to 50,000 users in three months.

Work Experience

Lead iOS Developer (Contract)

2020 - PRESENT
  • Developed software development toolkit (SDK), allowing users to add a custom keyboard to their app.
  • Created second SDK, which allows monetizing the keyboards.
  • Provided high test coverage to all features and continuous integration and automatic releases.
Technologies: Swift, SDKs, Frameworks, Custom Keyboards, Functional Reactive Programming, Unit Testing, Integration Testing

Senior Swift Developer (Contract)

2019 - 2020
Babylon Health
  • Developed on-the-door authentication using Auth0 with Face ID support.
  • Provided high test coverage for all developed features.
  • Supported the Babylon team with regular app releases.
Technologies: Coded UI Tests, Unit, Redux, ReactiveSwift, Swift

Senior Swift Developer (Contract)

2019 - 2019
  • Developed new features for millions of JustEat users.
  • Supported team with bi-weekly app releases.
  • Maintained apps by finding and fixing crashes and other issues.
Technologies: Optimizely, Firebase, Continuous Integration (CI), Coded UI Tests, Unit, Swift

Senior Swift Developer (Contract)

2018 - 2019
  • Developed Karhoo SDK, which is used for easy access to Karhoo API. It handles authentication, taxi quotes, booking, driver tracking, and journey updates.
  • Developed Karhoo UI SDK that extends Karhoo SDK with UI. The app is bundled as a framework and allows easy integration with partner apps.
  • Developed Karhoo App as a sample app that uses both SDKs.
  • Maintained high test coverage with Unit and Integration tests for all project mentioned.
Technologies: Development, Test-driven Development (TDD), Continuous Integration (CI), C, Viper, Swift

Senior Swift Developer (Contract)

2018 - 2018
  • Optimized the Olympic Channel app for iPhone X and shipped a couple of updates.
  • Joined Formula 1 app team and help them finish and polish the new app.
Technologies: User Interface (UI), Video on Demand (VOD), Functional Reactive Programming, Swift

Senior Swift Developer

2017 - 2018
  • Led and took ownership of Greenfield, a Swift project.
  • Chose to use MVVM architecture with reactive and functional programming to create readable, easily expandable, and highly testable code.
  • Ensured that the classes are decoupled as much as possible.
  • Used TDD approach to develop new features and achieved total project test coverage to around 80%.
  • Used state machine for navigation between different screens of the app.
  • Implemented a continuous integration using Bitrise CI. It automatically runs tests on pull requests and sends results to Github pull request page. Only PRs passing the tests (tests, swift lint, code coverage) can be merged in.
  • Pushed to master/develop branches to create a build and send it to iTunes.
Technologies: API Design, Continuous Integration (CI), Test-driven Development (TDD), Model View ViewModel (MVVM), Swift

iOS Swift Developer

2015 - 2017
Firefly Experience Limited
  • Developed a highly customized user interface with customized animations and use of Core Graphics.
  • Used customized maps (Mapbox) to present the user’s captured trails and points of interest.
  • Supported the designing of the app’s architecture, which was MVVM with reactive programming.
  • Implemented CI using onsite Mac Mini server.
  • Used Xcode Bots and Fastlane to make nightly builds, run tests and automatically create release builds.
  • Managed a great volume of user testing using Mixpanel and UXCam.
Technologies: Core Data, Core Location, Animation, Test-driven Development (TDD), Model View ViewModel (MVVM), Swift

Lead iOS Developer

2014 - 2015
  • Took ownership of the app when Uncover was in beta version with the final version featured multiple times by Apple as Best New App and Best Food App.
  • Implemented new features and highly custom animations.
  • Managed to successfully put down crashes to 0.02% of sessions.
  • Implemented Socket.IO to support live server updates inside the app.
Technologies: Socket.IO, Swift

iOS Developer (Contract)

2012 - 2014
  • Developed various projects within banking and eCommerce.
Technologies: User Interface (UI), Core Data, Model View Controller (MVC), Objective-C

PHP Developer

2008 - 2010
  • Developed new features and maintained the eCommerce software.
Technologies: MySQL, PHP


JustEat is a food delivery app supporting 40 million customers across 13 countries with revenue of $5.3 billion in 2018.

Babylon Health

Babylon believes it is possible to put an accessible and affordable health service in the hands of every person on earth.

Olympic Channel

App with live sports channels and video-on-demand streaming.

Formula 1

A new version of the official Formula 1 app.

Travel Spective

Apple TV app with travel videos on demand.


Karhoo is a taxi booking platform integrated with Taxi Fleets worldwide.

I worked on SDK that Karhoo partners can integrate into their apps and sample app that shows SDK integration.

Xendpay Money Transfer

Transfer money to over 170 countries in 50 currencies, including euros, US dollars, and British pounds. With our easy-to-use app, you can send money overseas from your iPhone or iPad anytime, anywhere.


The end of the desperate searches on the Internet. You can get almost anything on Alza. Everything conveniently in one place, right in your pocket.
2009 - 2014

Master's Degree in Computer Science

Technical University of Ostrava - Czech Republic

2012 - 2013

ERASMUS Program (Student Exchange Program) Participant in Computer Science

University of Aveiro - Portugal


Mobile App Security+ (iOS Edition) 



Firebase iOS SDK, CocoaPods, Alamofire, Fabric, Socket.IO, iOS Native Libraries


Xcode, SwiftLint, Instabug, Fastlane, Optimizely


UIKit, iOS SDK, Redux, Core Location, Viper, ReactiveSwift, Core Data


iOS, Bitrise, Mixpanel, Firebase


Swift, Objective-C, PHP, C, SQL, JavaScript


Test-driven Development (TDD), Dependency Injection, Mobile Development, Reactive Programming, Functional Reactive Programming, Coded UI Tests, Testing, Continuous Integration (CI), REST, Object-oriented Programming (OOP), Functional Programming, Model View ViewModel (MVVM), Model View Controller (MVC), Requirements Analysis, Unit Testing




Development, User Interface (UI), Debugging, Profiling, Carthage, Model View, iOS Animations, Code Architecture, Animation, API Design, Video on Demand (VOD), Unit, Teams, APIs, Architecture, Technical Leadership, SDKs, Frameworks, Custom Keyboards, Integration Testing, Computer Science

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