Mäuse

German slang for money. Literally: mice.

Say what you spent. That's it.

Mäuse is an expense tracker for couples with a built-in voice mode — just speak your expense and it's logged. No cloud, no account, no tracking. Everything stays on your phone.

"Paid forty-two fifty for dinner at Luigi's" — done.
Mäuse
March 2026
Total
847.50 €
Partner's share
423.75 €
Groceries
Mar 6, 2026
65.00 €
32.50 €
Restaurant
Mar 5, 2026
89.00 €
44.50 €
Electricity bill
Mar 1, 2026
120.00 €
60.00 €

Everything you need, nothing you don't

Quick Entry

Add expenses in seconds with a streamlined form. Amount, description, date — done.

Smart Splitting

Split by percentage or fixed amount. Preset chips for 50%, 30%, 70%, or 100%.

Voice Mode

Speak your expense, review the AI draft, save. The only feature that connects to the cloud — uses your own OpenAI API key for transcription.

Monthly Overview

See combined totals and your partner's share at a glance, month by month.

Three steps. That's it.

1

Log an expense

Type it in or use voice mode — just speak what you paid for

2

Choose how to split

By percentage or a fixed amount

3

Track monthly totals

See what your partner owes at a glance

Cancel Voice Expense
Tap to stop Listening…
Cancel Voice Expense Done
42.50
Description Dinner at Luigi's
Date Mar 7, 2026
Split 50%

No cloud. No account. Just your phone.

Mäuse runs entirely on your device. Your expenses never leave your phone — there's no server, no database, no sign-up. It's just code.

  • Local-first storage
    All expenses live in IndexedDB on your device. Nothing is sent anywhere.
  • Works offline
    Manual entry works without any internet connection. Open the app and go.
  • No account, no tracking
    No sign-up, no analytics, no telemetry. Zero data collection.
  • Portable backups
    Export your data as JSON. Import it on another device. You own the file.
  • One optional cloud connection
    Voice mode sends audio to OpenAI for transcription using your own API key. Everything else is 100% offline. The key stays on your device and is excluded from backups.

Open source. Read every line.

Mäuse is fully open source. No build step, no bundler, no framework — just vanilla HTML, CSS, and JavaScript you can read and verify yourself.

View the source on GitHub

Four files. No dependencies. No magic. Clone it, serve it, and it works.

index.html · style.css · app.js · voice-utils.js
Browse the Code

Built for your iPhone home screen

Mäuse is a Progressive Web App optimized for iPhone. Install it from Safari and it runs like a native app — full screen, fast, and offline-ready.

iPhone — Safari
  1. 1 Open pwa.mäuse.app in Safari
  2. 2 Tap the Share button
  3. 3 Tap "Add to Home Screen"
Full-screen standalone mode
Works offline after install
No App Store required