Latest post — June 2, 2026
All I Know about the Security Risk of Flutter Packages
Have you ever counted how many packages your project depends on? If not, run the command below in your terminal and check the number it outputs. The number is…
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All I Know About WidgetsApp
An entry point for independence from platform-specific design languages
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All I Know About AnimationController
The basic idea of Flutter's "explicit animation" is so simple: rebuild with updated value. Imagine if a Container has its size of width: 50, height: 50, it…
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Make Your build() Clean with StateHolder
If we take a closer look at build() method, we sometimes find it "messy", messy with calculation logics to create values even though we may want to focus on…
Tsuyoshi Chujo
Flutter app developer
I am a freelance mobile app developer based in Japan, working mainly with Flutter. Besides building apps, I write technical articles, speak at meetups and conferences, and run training sessions for engineers.
I enjoy digging into how Flutter works under the hood, such as Elements and BuildContext, and sharing what I find at conferences like FlutterKaigi and FlutterNinjas. I also maintain open-source packages such as crop_your_image.
Feel free to reach out by email for development or writing work.
My app
How Math Works
An iOS / Android app where elementary schoolers build an intuition for math by touch — rotating solids, folding nets and more. One of the experiences, unfolding nets, runs right in your browser.