Stderr is a catalogue of Java and Python programs that look correct and are not. It is built to collect nothing about you — no account, no sign-up, no tracking, no ads, and no analytics.
Nothing. There is no account to create and no email to enter. There are no analytics, advertising or tracking SDKs, and no third-party software of any kind — the app uses only Apple's own frameworks and has no Swift Package dependencies.
This is stronger than a promise not to send anything. The compiled app contains no networking code: no URLSession, no WKWebView, no CFNetwork. A script checks the source for those symbols before every release and fails the build if one appears. Put the device in Airplane Mode and every entry still works.
Nothing beyond the app itself. There is no progress to save, no history, no bookmarks and no settings that leave your device. The catalogue ships inside the app and is read-only.
The app collects no data from anyone, of any age.
If this policy ever changes, the updated version will appear on this page. Since the app collects nothing, there is not much that could change.
Questions: john@johnvdoan.com
Last updated 16 September 2026.