Katsumi Kishikawa
IOS Developer at ZOZO Technologies, Inc.
Tokyo, Japan
Summary
🤩
Rockstar🎓
Top SchoolKatsumi Kishikawa is a seasoned iOS developer with 17+ years building native iPhone and Mac applications, developer tools, and reusable libraries while actively maintaining popular open-source projects. Based in Tokyo, he combines deep expertise in CoreText, JavaScriptCore, CoreData and the Objective-C runtime with fluency in Swift, Objective-C and C/C++, enabling high-quality text, UI and database work across platforms including watchOS and tvOS. He has significant open-source impact—authoring widely used libraries like KeychainAccess and SpreadsheetView and contributing core fixes and build tooling to Realm. Beyond shipping apps, he focuses on developer ergonomics: backports, AST visualizers, CI improvements and test automation to raise code quality. Regular conference speaker on low-level topics like linking and AST meta-programming, he blends systems-level insight with practical UX improvements.
17 years of coding experience
17 years of employment as a software developer
Bachelor, Japanese Literature, Bachelor, Japanese Literature at Kobe University
Stackoverflow
10,503reputation
460kreached
215answers
0questions
xcode
top-5%
ios
top-1%
realm
top-1%
migration
top-5%
objective-c
top-5%
swift
top-1%
Github Skills (48)
unit-testing10
objective-c10
ios10
c-language10
porting10
image-processing10
testing10
databases10
bitcoin10
bitcoins10
ui-design10
coretext10
xctest10
security10
portable-database10
Programming languages (18)
Github contributions (5)
kishikawakatsumi/SECoreTextView
Apr 2013 - Apr 2015
SECoreTextView is multi style text view.
Role in this project:
Front-end Developer
Front-end DeveloperContributions:188 commits, 9 PRs, 9 pushes in 1 year 11 months
Contributions summary:Katsumi primarily contributed to the development and maintenance of the user interface within the `SECoreTextView` repository, specifically focusing on iOS compatibility. Their commits demonstrate a focus on implementing text selection features, text attachment support, and improving the overall visual appearance of the text view. The user also addressed several UI-related issues, including fixing long press behavior and ensuring correct font rendering.
text-styleandroid-libraryandroidios
kishikawakatsumi/PEPhotoCropEditor
May 2013 - Sep 2014
Image cropping library for iOS.
Role in this project:iOS Mobile Developer
iOS Mobile DeveloperContributions:93 commits, 2 comments, 1 issue in 1 year 4 months
Contributions summary:Katsumi primarily contributed to the development of an iOS image cropping library. Their work involved creating and refactoring UI components, implementing gesture recognition for image rotation, and adding features for constrained cropping aspect ratios. The commits demonstrate a focus on enhancing user interaction and refining the cropping functionality within the library. The changes also included addressing bugs related to device orientation changes.
ios
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