Folium
Folium Privacy Policy
Effective November 1, 2026 (updated for the Android app, and on November 3, 2026 to reopen the PDF you were working on and add the contact page)
Folium is made by Happy Heart Software LLC.
Your PDFs stay on your device
Folium opens, shows and changes PDFs in your browser on this device. Your files aren’t uploaded, and we don’t receive copies of them or of anything in them. When you annotate, fill in forms, sign, organize pages or merge PDFs, the new PDF is built on this device and saved where you choose. Images you add to a PDF are read from your device into the PDF, and go nowhere else. Passwords for protected PDFs are used only on this device to open the file, and aren’t saved.
What Folium keeps in your browser
The page you were last on in each PDF, so it opens there next time. It’s stored by an ID inside the file, with no file names or content, for up to 200 files. Clearing your browser’s site data removes it.
Signatures and initials you choose to keep for next time, as small images, up to five of each. Remove them in the signature window, or clear your browser’s site data.
The PDF you have open, so that if Folium is closed while you’re in another app or tab (phones and browsers do this to save memory), it opens again where you left off, with any changes you haven’t saved. Only one is kept: it’s replaced when you open another PDF and deleted as soon as you close it in Folium. PDFs that need a password are never kept. Clearing your browser’s site data also removes it.
A copy of Folium’s own files (the app, its fonts and PDF tools), so it works without a connection. PDFs are never kept there.
In the Android app
The app carries all of its own files, so it doesn’t load anything from the internet. It asks for no permissions: you pick each PDF to open, and choose where each one is saved, with Android’s own file picker.
When you open a PDF in Folium from another app, or share one to Folium, Android lets Folium read that one file. Folium copies it into its own private space on the phone to open it, and deletes that copy when you next open a file this way. Saving and sharing work the same way in reverse: Folium puts the PDF in its private space for a moment, then copies it where you chose, or hands it to the app you pick (that app’s own privacy policy covers what it does with it). The last shared PDF stays there until you share another, so the app you shared it with can finish reading it. No other app can see Folium’s private space, and Android may clear it when the phone needs room.
What the app keeps is the same as above (last pages, the signatures you choose to keep, and the PDF you have open until you close it), stored in the app on this phone. It’s left out of Android backups and transfers to a new phone. Uninstalling the app, or clearing its storage, removes it.
What is sent
Nothing, unless you write to us (below). Folium makes no requests about you or your files. On the web, it only loads its own files from folium.happyheartsoftware.com, as any website does, including a few font and image-decoding files that some PDFs need. The Android app sends nothing at all.
If you write to us on the contact page, what you type there (and your email address, only if you choose to include it) goes to Heartforms, Happy Heart Software’s own form service, which keeps it and emails it to us. We read it, reply if you gave an email, and use it to improve Folium; we never sell it or use it for advertising. To have a message deleted, email us. The contact page opens in your browser; the Android app itself still sends nothing. Heartforms’ privacy policy is at forms.happyheartsoftware.com/privacy.
What we don’t do
No accounts, analytics, advertising, tracking, cookies or third-party scripts in Folium. Fonts and all other files load from Folium’s own site.
Changes
If Folium ever sends anything, such as an optional Folium Plus feature you choose to use, this policy will say exactly what and when before that feature is available, and the date above will change.