Last updated: July 2026
These Terms of Service govern your use of the Zettelkasten app. By registering or using the app, you agree to be bound by these terms. If you don't agree, please don't use the app.
Zettelkasten is a progressive web app (PWA) for personal reading tracking and note-taking. These terms apply to the app and any related services offered by its operator, described in our Privacy Policy.
You must be at least 16 years old to create an account. If you're between 16 and the age of majority in your country, you confirm you have a parent or guardian's permission to use the app.
To use most features, you need an account, created via Google OAuth or with an email and password. You're responsible for keeping your login credentials secure and for all activity under your account. We may suspend or terminate accounts that violate these terms.
Core features are free. A paid Premium plan unlocks additional features, billed monthly or annually at the price shown at checkout. Payments are processed by Stripe; we never see or store your full card details.
Subscriptions renew automatically until cancelled. You can cancel anytime from Account settings — cancellation takes effect at the end of the current billing period, and we don't provide partial refunds for unused time. We'll give reasonable notice before any price change takes effect for existing subscribers.
You own the notes, quotes, lexicon entries, and other content you create in Zettelkasten. You grant us a limited license to store, process, and display that content solely to operate the app for you — for example, showing your own reading activity to accounts you're friends with, where that feature applies. We don't sell your content or use it to train third-party models.
You agree not to:
If you connect with other users by sending or accepting a friend request, your username, avatar, reading streaks, and reading activity become visible to them. You can control this by managing your friends or account privacy settings. We may remove content or restrict accounts that violate the acceptable use rules above.
Zettelkasten lets you import reading data from services like Goodreads. You're responsible for making sure you have the right to import that data; we treat it the same as any other content you add.
The Zettelkasten name, branding, and underlying software are owned by the operator and protected by applicable intellectual property laws. Nothing in these terms transfers ownership of the app itself to you.
The app is provided "as is" and "as available," without warranties of any kind regarding continuous availability or error-free operation. As this is a personal/independent project, liability for data loss or damages is excluded to the maximum extent permitted by law. Please back up important notes independently — the app's own export tools in Account settings make this easy.
You can stop using the app and request account deletion at any time by contacting support (see our Privacy Policy for contact details). We may suspend or terminate your access for violating these terms, with notice where reasonably possible.
These terms are governed by the laws of Germany, excluding its conflict-of-law rules. If you use the app as a consumer resident elsewhere in the EU, this doesn't deprive you of the protections mandatory consumer-protection law in your country of residence grants you. Where legally permitted, the courts of Germany have exclusive jurisdiction over disputes arising from these terms. We are not obligated to participate in dispute resolution proceedings before a consumer arbitration board and do not currently do so voluntarily.
We may update these terms as the app changes. Continued use of the app after changes are published constitutes acceptance of the revised terms; material changes will be reflected by updating the date at the top of this page.