Marcin Kmiec, Developer in Kraków, Poland
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Marcin Kmiec

Verified Expert  in Engineering

Software Developer

Kraków, Poland
Toptal Member Since
June 27, 2015

Marcin is a mobile software developer with ten years of professional programming experience. In addition to mobile apps he is pursuing game development, his lifelong passion, commercially. He has completed successful Unity projects (released for iOS and Android) and is open to new platforms. Marcin is able to deliver top-notch quality code as well as prioritize results over anything else.



Preferred Environment

Pivotal Tracker, Trello, Bitbucket, GitHub, Xcode

The most amazing...

...thing I've developed is emotion detection software covered by Techcrunch.

Work Experience

Mobile Unity Developer

2015 - PRESENT
  • Developed mobile apps for iOS and Android.
  • Led the development of a social app covered by Techcrunch and Al Jazeera.
  • Wrote a photo and video editing app with a million downloads.
  • Worked on a large Unity project that was released for iOS and Android.
  • Designed and implemented a compression algorithm for photo and video filters.
  • Coordinated back-end development for a number of apps.
Technologies: Unity, .NET, Kotlin, Swift, Android, iOS

Objective-C Developer

2015 - 2015
Michael Osofsky (via Toptal)
  • Developed a dating app from scratch.
  • Implemented pixel-perfect graphic design.
  • Worked closely with a distributed team.
  • Performed API tests and assisted during back-end development.
  • Handled submission to the App Store.
Technologies: Objective-C

Objective-C Developer

2015 - 2015
BookSwapper (via Toptal)
  • Developed an iOS app from scratch in Objective-C.
  • Developed a scalable Parse back end with custom cloud code.
  • Integrated in-house ads using MoPub.
  • Implemented scalable server-side search.
  • Handled the App Store submission process.
Technologies: JavaScript, Parse, Objective-C

Swift Developer

2015 - 2015
Spooky, Inc. (via Toptal)
  • Developed an iOS app using Alamofire networking framework.
Technologies: Swift

iOS Developer

2014 - 2015
  • Developed new as well as analyzed and improved existing iOS applications in Objective-C using a number of frameworks and technologies including Core Data, multithreading (GCD, NSOperation), and multiple communication stacks.
  • Created an augmented reality app for a car manufacturer using Metaio framework.
  • Ported a BlackBerry app into iOS with full data encryption.
  • Worked on a quiz application that used websockets to maintain the connection with the web service in real time.
  • Used unit and functional tests in a continuous integration environment.
Technologies: Objective-C

iOS Developer

2013 - 2015
  • Developed a location tracking app with continuous background location updates and balanced battery usage.
  • Coordinated web service development with an external developer.
  • Wrote an iOS client of a popular social news website that's nearly topping the US App Store chart in its highly competitive category.
Technologies: Objective-C

Computer Vision Researcher

2011 - 2014
AGH University of Science and Technology
  • Performed research on object detection in images.
  • Implemented various computer vision algorithms in C/C++ using OpenCV.
  • Designed software architecture of a real-time computerized CCTV system.
  • Created an in-house image database accesible through a RESTful API.
  • Performed code reviews.
Technologies: OpenCV, C++

PhD Student Contractor

2009 - 2012
ABB Corporate Research Center Krakow
  • Developed embedded software for power-grid control devices.
  • Designed, developed, and maintained user-friendly C/C++ software libraries.
  • Integrated third-party middleware.
  • Developed reference designs.
  • Supervised junior developers.
Technologies: C++, C

Polygram was a social app that detected facial reactions to shared photos and videos.

Portal App

An augmented reality application running on iOS and Android, developed in Unity3d.

Liveclip iOS

A live photo editing app for iOS.

Liveclip Android
A motion picture editing app for Android.

Book Swapper

An app aimed at college students allowing them to buy and sell their textbooks. Developed both the iOS app and Parse back end with JavaScript cloud code.

Hacker News Client

A client on the App Store using the official Firebase API. A very successful app with a lot of reviews and a five-star rating in the US.

CoffeeOrBeer App

A location-based app using Square API and Google Maps SDK.

Augmented Reality iPad App

An iPad app using Metaio augmented-reality framework used to train car dealers in Germany.


An iOS location tracking app with continuous background location updates and balanced battery usage developed for a restaurant in Ireland to optimize their food delivery process.

iOS Secure Data Storage App

An application aimed at corporate users to securely store classified information.

Scientific Journals Search Engine for Poland's Scientists

I developed this site back in 2012 to solve my own problem of searching through a PDF list of some 20,000 scientific journals, which took forever. I scrobbled the list into a MySQL table and implemented a search as you type with JavaScript and PHP. The website went viral and now enjoys around a thousand visits a day.

Tutorial on Using RESTKit Framework with Core Data
This blog post of mine aimed at intermediate iOS developers has made it to the first page of Google results for "RESTKit tutorial," enjoys roughly a hundred visit a day, and has been recommended by numerous developers.

Portal AR

An augmented reality Unity application released for both iOS and Android.

Football Royale

A mobile game written in Unity released on Android, with an iOS release in the works.


Swift 4, C, C++, Objective-C, Java, Kotlin, C#.NET, Swift, C#, PHP, JavaScript


Core Location, iOS SDK, AFNetworking, Swagger, .NET, Unity3D, Core Data, Unity


Parse SDK, OpenCV, Alamofire, Socket.IO


Git, Xcode, GitHub, Bitbucket, Trello, Pivotal Tracker




Firebase, iOS, Android, Parse


User Interface (UI), Front-end, SAP SD, WebSockets


Realm, MySQL

2004 - 2009

Master of Science Degree in Computer Science

AGH University of Science and Technology - Krakow, Poland

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