Backup and restore are here
Until now, My Weight Tracker could export your weigh-ins as a CSV, handy for a spreadsheet, but there was no way to bring that data back. Switch phones, reinstall the app, or clear your browser, and you started again from a blank slate. That's fixed today: Settings has a proper Download backup and Restore from backup, and restoring is also right there on the very first screen, before you've set up anything at all.
Take your trail with you
Open Settings and tap Download backup to save a file with every weigh-in, your unit preference, and your goal weight. Keep it in Files, a cloud drive, or email it to yourself, wherever you'd normally keep something you don't want to lose. On a new device, or after a reinstall, open My Weight Tracker and tap Restore from a backup instead on the start screen, pick the file, and your whole trail is back exactly as it was. The CSV export is still there too, for anyone who wants the numbers in a spreadsheet.
Still just yours, still just on your device
Nothing about how the app handles your data changes here. There's no account, no server, and nothing is ever sent anywhere automatically: the backup file only moves if and where you choose to put it. Restoring simply reads that file back into the browser's own storage on whichever device you open it on. It's the same privacy-first approach My Weight Tracker has always had, just with a way to carry it with you now.