Nearly every money app now opens by asking you to log into your bank through an aggregator, which means handing a third party read access to every transaction you make. Plenty of people would rather not, and then struggle to find an app that works without it.
There is no bank integration to turn off
Keep the Diff has no bank connection feature at all, optional or otherwise. There is no aggregator, no credentials field and no transaction feed. The app physically cannot read your spending, which is a stronger promise than a setting.
So where do the numbers come from?
You type them, and only when you want to. Two per entry: what you were ready to spend and what you actually spent. The difference is recorded as money you kept. Those two numbers are less data than any aggregator app holds about you, and they are the only data there is.
What else the app does not do
- No account needed. You never sign up or create a password, so no account of yours can leak in someone else's breach.
- No analytics. No usage tracking, no third-party crash reporting SDK, no session recording. A crash report goes only if you say so.
- No advertising and no advertising identifier. Nothing is sold or shared, because nothing is collected to sell.
- No third-party SDKs that phone home.
The two times the app uses the network
Unlocking Premium on a Mac or a PC, and only if you ask it to. That request carries a short code and the opaque receipt number your app store issued, so the server can ask Apple, Google or Stripe whether the subscription is live. It carries nothing you have logged.
Premium sync between your own devices, and only if you turn it on. Everything is encrypted on the device before it leaves, with a key that only your devices hold, so the server keeps a sealed copy it has no way to open. If you never unlock a computer and never turn on sync, the app does not use the network.
The privacy policy says the same thing at greater length, and it is one page.
Where your data lives
In the app's own private storage, on the device you logged it on. On Apple and Android your log is included in your own iCloud or Google device backup, the same as any other app's data, and that backup belongs to you and your device maker. Premium exports the lot as a CSV whenever you want it.