Free, open source, for Mac

Couple finances, in harmony.

Duet is a private money app for two. Bring in your bank statements, sort each purchase into Ours or Mine, and see where your money goes each month. It lives on your own Macs: no bank logins, no ads, no one else's cloud.

Download for Mac Try the demo

The latest version · macOS 13 or later · Apple silicon and Intel

Duet's month view: $7,842 spent in August, the categories against a typical month, what was Ours and what was each person's, and the last six months.

Made for two

Each of you brings in your own statements. Duet puts together the month you share, and keeps what's yours, yours.

Ours and Mine

Every purchase is Ours or Mine. Mine stays personal: your partner sees only its totals, never the shops.

Ebb & flow

See who has carried a little more toward Ours, against Our rhythm, the split you set from your incomes. No debts, no due dates: a Clean slate whenever you like.

Statements, not bank logins

CSV, Excel and OFX files from ten US banks and cards, read on your Mac. Duet never signs in to your bank.

Sorting that learns

Your rules, your own history and a starter pack sort most rows. Local models on your Mac mini help with the rest, and nothing is sent anywhere else.

Encrypted end to end

A Mac mini at home passes changes between your two Macs without being able to read them. Each of you keeps a 24-word recovery phrase.

Open source

Every line is on GitHub under the AGPL, and the bank readers under MIT. Built with Claude Code.

A calm look at the month

Sort with the keyboard, see what a typical month looks like for you, and watch Ebb & flow over time.

To sort: a statement's rows with suggested categories, their confidence, and Ours or Mine.
To sortSuggestions with how sure they are. O for Ours, M for Mine, and a rule when you want one.
Trends: twelve months by category and person, with a typical month for us.
TrendsTwelve months at a glance, and a realistic month for the two of you.
Ebb & flow history: each month's figure and the running total, with Clean slates marked.
Ebb & flowMonth by month, with every Clean slate along the way.
Open Jack and Jill's year in the demo

Set up in an evening

Duet works on one Mac straight away. Add a Mac mini when you want the two of you in step.

Install Duet on your Macs

One line in Terminal, or the download below. Updates arrive in the app.

Give it a Mac mini

An always-on Mac on your Tailscale network relays changes and runs the sorting models. The setup guide takes you through it.

Send a join link

Your partner opens it, installs Duet and joins your household with its own recovery phrase.

Your money stays at home

Duet has no servers of its own and no accounts. Your data lives on your Macs, and the only other copy is on your own Mac mini, encrypted with keys it doesn't have.

  • On your MacsStatements are read and kept on the Mac they were brought in on.
  • Encrypted before it leavesXChaCha20-Poly1305 with a household key only your recovery phrases open.
  • Nothing watchingNo analytics, trackers or ads, in the app or on this page.
  • Yours to inspectduet export turns everything into JSON, CSV and SQLite with a recovery phrase.

Get Duet

Free, for macOS 13 or later on Apple silicon and Intel.

From Terminal Recommended

One line downloads the latest release from GitHub and puts Duet in Applications, with nothing extra to allow.

$ curl -fsSL https://firstprateek.github.io/duet/install.sh | sh

Open Terminal from Applications → Utilities, paste, and press Return.

As a download

Duet isn't notarized by Apple (that needs a paid developer account), so macOS asks once before opening it:

  1. Open the download and drag Duet to Applications.
  2. Open Duet. When macOS stops it, open System Settings → Privacy & Security.
  3. Next to the note about Duet, choose Open Anyway.
Download for Mac All releases

Updates arrive in the app, and each one is checked against Duet's own signature before it installs.