Consulting Services

Hi, my name is Matthijs. I’m currently available as a freelance audio developer.

Previously I’ve also worked on machine learning for mobile devices, iOS apps, websites, enterprise software, games, embedded systems, and much more.

Location: Netherlands (looking for remote work only)

ACM, IEEE, and AES member.

Contact me by emailGitHubLinkedIn

What can I do for you?

I can help you with:

I can write the code and/or consult on the best ways to solve technical problems, or consult on the usability and design of your software.

Technologies I typically use:

I’m an all-round developer with many years of experience, and picking up new technologies and learning new skills is part of the fun for me.

Audio projects I’ve worked on

Work history

Machine Learning Engineer, Hugging Face (2022–2023) As part of the audio team, I added new speech models to the Transformers library. Co-authored the Audio Course, teaching developers how to do machine learning with sound. Developed methods of exporting Hugging Face models to Apple’s Core ML.

Freelance Machine Learning Consultant (2017–2022) I helped clients add machine learning to their iOS apps, implementing neural networks from scratch in Metal and Core ML and optimizing them for mobile, with a focus on real-time computer vision and fast inference. Tech used: Python, PyTorch, TensorFlow, Core ML, Metal, Swift, C.

Author of Books and Tutorials (2011–present) I’ve written for the popular e-learning website (now Kodeco), my own blog, The Audio Programmer, and self-published through Leanpub.

Senior Software Engineer, Concepts-ICT (2008–2010) Worked on internal software that was used to automate and streamline the company’s business processes. Also built the website and backend for the ADSL!Totaal internet service that was provided in cooperation with the magazine Computer!Totaal. Tech stack: PHP, HTML, CSS, JavaScript, PostgreSQL.

Independent App Developer (2002–present) Self-employed, making my own software products and selling them online. Tech used: C++, Objective-C, Swift, UIKit (iOS), AppKit (Mac), Win32.

Senior Software Engineer, Virtual Unlimited (1998–2002) Developed a platform for secure internet applications that ran inside a dedicated application instead of the web browser. I was primarily responsible for the visual development tool that let third-party developers build apps on this platform.

Hobbyist Game Developer (1985–2014) Wrote my own games for fun, first in BASIC, later in assembly. Notable releases: Mahjong Cards, played over 20 million times (iPad, 2014); Ultimate Countdown with over 250 thousand downloads (iPhone, 2008); Zero Gravity, a fast-paced 3D tunnel flying game (Amiga, 1997).


I like explaining things and have written several books.

Principal author of:

Co-author of:

Tutorials published at the popular development website (now Kodeco):

My own blogs:

I’m also the founder of Swift Algorithm Club, which now has 28k+ stars on GitHub. Detailed explanations of algorithms and data structures in Swift.