Privacy

Leaf goes on the network by itself for one thing only: anonymous counts of how many copies are installed and in use. You can turn it off. Your documents never leave your computer: Leaf opens, edits, recognizes and saves them all by itself.

Usage counts

Leaf sends a short message to stats.syncster.dev, a service we run:

• When it's installed or updated: once, the first time it runs on a computer, and once more the first time it runs as a new version.
• When it's used: at most once a day, on a day you use it.

Each message carries:

The id is random digits made the first time Leaf runs. Nothing about you or your computer goes into it: it only tells one copy of Leaf from another, so each is counted once. A value Leaf can't find out is left out.

The service works out the country from the network address a message comes from, and stores the country only. The address itself is never stored.

Turning them off

Untick Help ▸ Send Anonymous Usage Statistics and no more usage messages are sent. They're also never sent when the environment variable LEAF_NO_STATS=1 or DO_NOT_TRACK=1 is set.

Updates

Leaf looks for a new version as it starts (at most once an hour) and every six hours while it's open. It reads one small file, https://storage.googleapis.com/leaf-releases/updates/latest.json, which says what the newest version is; nothing about you or your computer is sent with it. When a newer version is out, Leaf downloads it from the same place, checks it against the checksum in that file, and installs it when you quit (on macOS, only an app signed by Leaf's developer is ever put in). Help ▸ Check for Updates Automatically and Help ▸ Install Updates Automatically turn this off.

What is never sent

• Your documents, or anything in them: text, pictures, comments, form entries or signatures
• File names, folder names or paths
• Your name, email address, user name or computer name
• What you do in Leaf: no tracking of commands or clicks, no crash reports

OCR, compare, compress and every other tool run on your computer, with Leaf's own code. Leaf has no accounts and shows no ads, and nothing is sold or shared.

When you ask

• Links in a document: clicking a web link in a PDF opens it in your web browser.
• Help ▸ Leaf Website and the syncster.dev link in About Leaf open those sites in your web browser.

On your computer

Leaf keeps a few small files in its data folder: its settings and the list of recent files (prefs.json) with a small picture of each one's first page for the start screen (recent/), the signature and initials you chose to save (signature.json, initials.json), and the usage-statistics id, last reported version and switch (stats.json). Work files for a job in progress go in temp/.

This website

Pressing a download button tells the same statistics service that Leaf was downloaded: the product, the version and the system it's for (macOS or Windows). Nothing about you is in it. The website sets no cookies and runs no ads or trackers. Besides that service, which the home page also asks for the number of installs to show it, it loads nothing from other sites. It's hosted on Netlify, and downloads are served from Google Cloud Storage (storage.googleapis.com).

Questions: syncster.dev. Last changed 1 November 2026.