GitHub: https://github.com/duck-psycho/nsz-converter
My first venture into the Nintendo Switch world, though without actually developing for Horizon. I was exploring NSZ and testing Cursor with the Composer model. The result is a fairly elegant user solution, with the app package weighing in at just 1.23 MB.
NSZ Converter converts Nintendo Switch files from the compressed NSZ format to NSP without requiring prod.keys.
The app is free and ad-free, but it remains closed-source because I want to prevent anyone from re-skinning it or republishing it on Google Play under their own name.
Initially, the only permission required was write access to the selected directory. However, since version 1.2 introduced update checks, it now requires network access — but strictly to fetch data from https://github.com/duck-psycho/nsz-converter/releases.
Update: July 5, 2026
GitHub: https://github.com/duck-psycho/nsz-converter/releases/tag/v1.2
Version 1.2 introduces the following changes:
- Support for batch-converting entire folders, including nested subdirectories.
- The selected output path is now saved, so you don’t need to grant directory permissions every time.
- A brand-new theme inspired by the Nintendo Switch design.
- Automatic update checks via GitHub Releases.
- The “Support the Developer” message is no longer shown on the first launch, and its frequency has been reduced to every 5th launch.
Screenshots
