A money saving app for Android that never asks for your bank

Nearly every money saving app on Google Play begins the same way: create an account, then hand over read access to your bank so it can categorize what you already spent. Keep the Diff does neither. There is no account, and it cannot connect to your bank because there is no bank integration in it at all.

It also records the opposite thing. An expense tracker can only show you money leaving. The decisions that stop money leaving are invisible to it, even though they are the whole reason there is anything left at the end of the month.

What it does

You log two numbers: what you were ready to spend, and what you actually spent. The difference is the Diff, and it is recorded as money you kept. It adds up by week, by month, and toward whatever you are saving for. Logging one takes three taps.

Buy the thing anyway and nothing happens. There is simply no Diff that time. No budget to exceed, no streak to break, and no red number, because the lowest a week can read is zero.

Spent less rather than nothing at all? That counts too. Ninety dollars planned and forty spent is a fifty dollar Diff.

On Android specifically

• A real Android app, built with Jetpack Compose. Not a web page in a wrapper, and not the iPhone layout in a costume.
• Home screen widgets. This week's Diff on the home screen, so the total is something you pass rather than something you open an app to check.
• Phones and tablets. On a tablet the content holds a single reading column instead of stretching a phone layout to ten inches, so the line length stays readable and the buttons stay where your thumb is.
• Two permissions, both optional in practice. The app declares biometric unlock and a wake lock, and nothing else. No location, no contacts, no SMS, no notification access, no accessibility service. The one file it ever reads is a single photo, and only if you attach one to a goal yourself.
• It works offline, permanently. Not an offline mode you switch on. Everything you log is written to the device and nothing you log is ever uploaded, so a plane, a basement or a dead SIM changes nothing about what the app can do.

Your numbers stay on your phone

No account, no sign-in, no analytics, no tracking and no advertising identifier. Everything you log is written to the app's own private storage on your device. The only time the app talks to the internet at all is when you buy Premium, and Google Play handles that.

If your phone backs itself up through Google, that file is included in the backup the same as any other app's data. That backup is yours, and we cannot see inside it. The full privacy policy is one page and says the same thing at greater length.

Free, and what Premium adds

Logging decisions is free and always will be, with no ads and no limit. So is this week's total, this month's, your recent history, and the weekly recap card you can share.

Premium adds your full history with CSV export, categories and breakdowns, unlimited goals with a photo of the thing you are saving for, and home screen widgets. One subscription covers every device you own. See Premium pricing, which is cheaper bought on this site than in a store, because a direct sale pays no platform commission.

It is not Android only

The same app runs on Mac and Windows as a direct download, and iPhone, iPad and Apple Watch versions are on the way. One Premium subscription covers every device you own.

Try it in your browser first if you would rather not install anything, or read what to look for in a no spend challenge app.