Cross-platform. Works on iOS, Android, and the web.
Dropbox is the most reliable cross-platform path. If you already pay for Dropbox or have it installed, this is the shortest setup of any non-Apple option. The same workflow also covers OneDrive (and any other sync service that gives you a regular folder on disk).
Step 1: Install Dropbox on your computer
If you don't already have Dropbox installed, grab the desktop app from dropbox.com/install.
Sign in. The installer creates a Dropbox folder on your computer (usually ~/Dropbox on Mac and Linux, or C:\Users\YourName\Dropbox on Windows).
Open the Dropbox folder once to confirm it's syncing. You should see the green checkmark icon next to fully-synced files.
Step 2: Point Keepance at Dropbox
In Keepance, open File → Open Workspace.
Navigate to your Dropbox folder.
Create a new folder called Keepance inside Dropbox (or pick an existing one).
Select the folder and click Open.
Every Markdown file Keepance writes from now on lives in Dropbox and syncs automatically.
[Screenshot: Keepance with workspace pointing at Dropbox folder]
TODO: real screenshot of Keepance's workspace selector pointing at the Dropbox folder.
Step 3: Wait for sync
Open the Dropbox folder in Finder or File Explorer and watch for the green checkmark next to your Keepance folder. Markdown files are tiny, so this usually finishes in seconds.
[Screenshot: Dropbox iOS app showing the synced Keepance workspace]
TODO: real screenshot of the Dropbox iOS app browsing the Keepance folder.
Limitations to know
Treat your phone as read-only for now. Dropbox handles conflicts more gracefully than iCloud (it creates a clearly labeled "conflicted copy" instead of silently making a duplicate), but the cleanest workflow is still to edit on one device at a time.
Dropbox free tier is 2 GB. A Keepance workspace fits easily, but watch out if you also store photos or large files in the same Dropbox account.
Smart Sync (selective sync) can hide files from Keepance. If you've enabled Smart Sync to keep files cloud-only, Keepance won't see them locally. Right-click the Keepance folder in Finder and choose Make Available Offline to force a local copy.
Sync icons matter. If you write a file in Keepance and immediately open the phone, the green checkmark on the desktop side confirms the file has finished uploading. Wait for it before checking the phone.
OneDrive note
OneDrive works exactly the same way. Install OneDrive on your computer, point Keepance at a folder inside the OneDrive sync folder, and use the OneDrive iOS or Android app to browse on your phone. The steps above translate one for one.
What's next
If you want a sync option that doesn't depend on a third-party cloud, see the Syncthing guide. If you have an iPhone and a Mac, the iCloud Drive guide is even simpler.