Matthias Keiser

I'm a software consultant from Switzerland (iOS, OS X macOS, POSIX, JS, web). I serve as Chief Product Officer for a start-up that just made Entrepreneur's 360™ list. If you ever played a mobile video with VLC, you have probably run code I wrote. I'm available for consulting work (in Switzerland or remotely). Contact me.


Tristan Inc. currently sells one app:


FSMonitor is a macOS app that monitors all changes in the file system. Learn more.

Client Work

SkilRoute video player

I developed the SkilRoute video player for both iOS and OS X, which shows up to four video streams simultaneously and allows you to life resize the individual streams. More info is available at the at the SkilRoute website.

Soon to be available on the AppStore.

SkilRoute video recorder

I also developed the SkilCapture video recorder and video editor for OS X. It is able to simultaneously record up to four videos from connected USB cameras or nearby iOS devices running a companion app. It is also a multi track video editor which is used to produce the videos for SkilRoute.

Soon to be available on the AppStore.


airfy beacon is a home automation app that uses Apples iBeacon technology to control the environment, for example Phillips Hue® lights. It's available on the AppStore.


Sonja is a unique music education app. It lets you read, write, record, and edit music easily, and you don't have to know music theory or notation. It's available on the AppStore.

What people say about me

“Matthias has terrific work ethic and pours his heart into the work he undertakes. He has almost always over-delivered on his promise. Within the first few interactions and short time working with him, I came to completely trust his work and commitment.I look forward to working with him as much as I can.”

- Raghav Badinger, CEO SkilRoute.

“Matthias is a awesome iOS coder and a great communicator. An absolute pleasure to work with. Really absorbed the spec and had great suggestions. Highly recommended!”

- Daniel Swirsky, AlphaPatent Associates Ltd.

Open Source


I contribute to the VLC media player. I'm the author of the CoreAudio demuxer module. I also contributed a series of patches to correctly handle rotated videos (as produced by i.e. iPhones). It made the VLC maintainer happy.


A swift module that makes it more convenient to work with Universal Type Identifiers. It's available on GitHub and CocoaPods.

Swift BinarySearch

Native binary search is curiously missing from the Swift standard library. I released a module that fills in that omission. It's available on GitHub and CocoaPods.


I released a small iOS component that implements a tab view as seen in Mobile Safari. It is very flexible and uses an intuitive API thats inspired by iOS' UITableViewSource. It's available on GitHub and CocoaPods.


Matthias Keiser

twitter: @mtthsksr