Jeff Holtzkener
Software Engineer
Toronto, Ontario, Canada
Summary
👤
SeniorJeff Holtzkener is a software engineer and iOS specialist with 11 years in the industry and 6+ years focused on shipping native apps, including five App Store releases such as the music app Concentric Rhythm. Based in Toronto, he blends deep Swift, Objective-C and SwiftUI expertise with audio and multimedia work—evidenced by meaningful contributions to the widely used AudioKit project (multi-touch keyboard, MIDI/Audiobus integration, AKSequencer improvements). A passionate accessibility advocate, he prioritizes inclusive UX through UIAccessibility and rigorous testing (XCTests/XCUITests). Comfortable across the stack, he pairs mobile UX work with backend and tooling experience in node.js, Firebase and CI automation. He’s an active open-source contributor and maker who treats software craft as both a technical and social responsibility.
11 years of coding experience
Stackoverflow
2,215reputation
37kreached
50answers
23questions
Github Skills (13)
midi10
midi-instrument10
audio10
swift10
ios10
user-interface10
audiokit10
graphical-user-interface10
human-interface10
xcode6
audiounit6
accessibility6
coreaudio6
Programming languages (5)
Github contributions (5)
AudioKit/AudioKit
Feb 2017 - Nov 2018
Audio synthesis, processing, & analysis platform for iOS, macOS and tvOS
Role in this project:
iOS Mobile Developer
iOS Mobile DeveloperContributions:53 commits, 16 PRs, 13 comments in 1 year 9 months
Contributions summary:Jeff contributed significantly to the user interface of the AudioKit framework, specifically focusing on the implementation of a custom keyboard view (AKKeyboardView). They added multi-touch functionality and keyboard modes, implemented new methods, and refactored several elements related to keyboard functionality and touch input. Moreover, the user integrated Audiobus MIDI sender functionality into a project using the framework. Additionally, the user made modifications to the MIDI file loading and track management within the AKSequencer component.
swift-playgroundsapplemusicmidisynthesisios
crashingbooth/ModalJazz
Mar 2015 - Sep 2018
Contributions:23 commits, 11 pushes, 1 branch in 3 years 6 months
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