Privacy

The short version

Your book is built in your browser. The finished PDF or EPUB is never uploaded to us. You do not need an account. If you make one, the book you are working on is saved to your library so you can open it later.

What passes through our servers

• URLs you paste. Our server fetches the publication’s feed, the articles you select, and their images, then hands them to your browser. Browsers cannot fetch these directly. We do not store article text or images.
• Your draft. The article list, your selection, and your design settings are saved in your browser’s local storage, on your device. Clearing site data removes them.
• An imported archive. A Substack export you import is opened in your browser and kept in this browser’s storage. The file itself is never uploaded. When a post is needed for the preview or an export, that one post’s HTML is sent to our server to be converted and is not stored.

What we store

• Account, if you make one. Email address, name if you give one, and sign-in method, held by our authentication provider.
• Your library, if you are signed in. For each saved book: the title and author, the list of articles with their titles and links, your chapter order, your chapter edits, and your design settings. Not the article text or images, apart from edits you typed. You can delete a book from the library page.
• Rate limiting. Your IP address is used briefly to limit abuse of the fetching endpoints.
• Things you send us. Messages from the contact form: your name, email address, and what you wrote. They arrive as email and are not kept in a database.

What we do not do

• We do not log exports or store the finished book files.
• We do not sell personal data.
• We do not run advertising trackers.

Who processes data for us

• Clerk for sign-in and account storage.
• Vercel for hosting.
• Neon for the database that holds saved books.
• Upstash for rate limiting.
• Resend for delivering contact form messages.

Your choices

You can delete saved books from the library page and delete your account from the account menu. To ask what we hold about you, use the contact form.

Changes

If this policy changes in a way that matters, the date above changes and signed-in users are told.