The household planner for people who share costs unevenly — and want the maths
to be right. Rent by income, electricity down the middle, the gym only one of
you uses. Every item gets its own rule, and both of you see what it costs
while you type.
Exact to the cent — no float ever touches moneyLinux, macOS, Windows — amd64 and arm64No telemetry, no external callsMIT licence
The current month at a glance — and any other month, because every entry
knows which months it applies to.
The problem
Every tool gets this half right.
Splitting apps assume one rule for everything. Spreadsheets can express it —
until one cell slips and the formula is quietly wrong for months. KassenKnoten
makes the split a deliberate choice per item, computes it to
the cent, and shows you the result while you type.
Every cost its own rule
Fixed quota or proportional to income — chosen per item, never assumed.
The household default only pre-fills the form.
Exact to the cent
Amounts are whole cents, shares are basis points. 39,99 € down the middle
becomes 20,00 € and 19,99 € — never 39,98 €. The calculation engine is a
pure, tested module.
The past stays honest
Every entry carries the months it applies to. A raise in September leaves
August reporting August — and the app asks whether a change is new from
now on or was always true.
Variable costs, two ways
Groceries, fuel, going out: either the plan counts — or every receipt with
its date, and the plan becomes the budget you measure against.
Scan a receipt
Photograph it and the total, the date and the shop are filled in. Read on
your own server — the photo is never uploaded anywhere and never stored.
Month by month
Twelve months in one chart. Drag along it and each month's income, costs,
savings and free cash follow — no navigation, no page load.
Every rhythm normalised
A 132,00 € yearly insurance sits next to everything else as 11,00 € a
month. Nobody divides by twelve in their head again.
Save on purpose
Savings pots with a monthly rate, a balance and an optional target — owned
by one person or by the household.
Calm warnings
Negative free cash, a savings rate above income, an overspent budget — as
a calm banner, not a modal. Deleting offers “Undo” instead of asking “are
you sure?”.
Sign in your way
A household password with an optional one-time code, Authentik or any
other OpenID Connect provider — or both, switched in the settings.
Installable as an app
Own icon on the home screen, opens without an address bar. Browsers that
cannot install a web app are told where the option lives in their own
menu.
English or German
Chosen when you set up and changed whenever you like. The language belongs
to the household, not to a browser — the tablet in the kitchen speaks the
same one as the laptop.
Extend it with your own code
Upload an extension and it contributes cards to the overview. It runs on
your server with full access — install only what you have read, or what
comes from someone you trust.
Backed up every day
One SQLite file on a volume you control. The server keeps the last
fourteen states of your data beside it — download one, restore it in one
step.
Shared fixed costs
Who pays what — and why.
Every shared item shows both shares in euros and percent, and which rule
produced them. The split is previewed as you type, by the same function
that later saves it — a preview that calculates a second way is a preview
that can disagree with the result.
Fixed quota or by income, decided per item
Largest remainder: the shares always add back up to the total
Private and shared kept cleanly apart
Month by month
The past, one drag away.
Every entry knows the months it applies to, so every month can be shown as
it really was. The overview draws the last twelve — drag along the chart,
or use the arrow keys, and that month's figures follow.
Income, fixed and variable costs, savings rate and free cash
A raise in April changes April on, not the months before
Every figure also listed underneath, for reading without a chart
Variable costs
A plan, or every receipt.
Anything that is not the same every month gets a budget — and you decide
per budget how it is kept. Plan counts the figure you set
and asks nothing more. Detailed counts what was actually
booked, every expense with its date.
The mode is a badge on the card, not a setting in a dialog
Booked against planned, always side by side
Split between you exactly like a fixed cost
Receipts
Photograph it. Check it. Save.
Scan receipt opens the camera, and the total, the date
and the shop come back filled in. The one question left is which budget it
belongs to — the budget carries the split, so that stays your decision.
Read by an OCR engine inside the container, in German and English
No key, no cloud service; the photo is dropped once it is read
What it could not read stays empty and says so
Savings
Saving you can see.
Pots with a rate, a balance and an optional target. Progress is a bar
rather than mental arithmetic — and when a pot passes its target, the
overview says so kindly.
Settings
Everything else, sorted.
Language and appearance, the default split and categories, sign-in,
backups and extensions — each on its own page, all listed on one overview.
On a wide screen the list stays beside you.
Switch sign-in methods and keep the allowlist without a restart
Download any of the daily backups, restore in one step
Settings that could lock you out refuse to
On a phone
Designed at 375 px, not shrunk to it.
A household plan gets opened in the kitchen, not at a desk. Same features,
navigation within thumb reach, an amount field that brings up the number
pad, and a design that follows the system theme.
Light and dark, following the system
Installable as an app, with its own icon
Offline it says so, instead of showing yesterday's figures
Security
They are your figures. They are treated that way.
Password and a second factor
One household password, hashed with argon2id and read from the environment
— a copy of the database is not a copy of the password. Optionally a code
from any authenticator app (TOTP, RFC 6238). A code that has been used is
refused.
Your identity provider
OpenID Connect with PKCE, the ID token checked against the provider's
keys, and only addresses on an allowlist kept in the app get in. Taking
someone off the list ends their session on the next click.
Encrypted session
The session cookie is encrypted, not merely signed (JWE, A256GCM),
httpOnly,
SameSite=Lax and
Secure over HTTPS.
Everything closed but what must be open
Every route but the login and the health check requires a session — deny
by default, so a new page cannot accidentally be public. Server actions
check again themselves.
Nothing from outside
A Content-Security-Policy with a per-request nonce, self-hosted fonts, no
CDNs, no telemetry. The container runs as an unprivileged user.
Checked before it ships
No image is published before the tests pass and a real browser has signed
in, set up a household and checked a split on the phone layout — against
the very server the image runs.
Self-hosting
Docker and two minutes.
No checkout, no Node, no build. The image is published for amd64 and arm64 and
runs wherever Docker runs Linux containers: a Linux server or NAS, a Raspberry
Pi 4 or 5 with a 64-bit OS, a Mac, or Windows with Docker Desktop. Both images
are started and tested in a browser before every release. Download two files,
generate the secrets — the scripts for that run inside the image — and start.
Linux and macOS
mkdir kassenknoten && cd kassenknoten
curl -LO https://github.com/jankln/KassenKnoten/releases/latest/download/docker-compose.yml
curl -L -o .env https://github.com/jankln/KassenKnoten/releases/latest/download/env.example
# a session secret, appended to .env
docker run --rm ghcr.io/jankln/kassenknoten:latest \
node scripts/session-secret.ts >> .env
# your household password, hashed — paste the printed line into .env
docker run -it --rm ghcr.io/jankln/kassenknoten:latest \
node scripts/hash-password.ts
# optional: a second factor, prints a QR code into your terminal
docker run -it --rm ghcr.io/jankln/kassenknoten:latest \
node scripts/totp-secret.ts
# optional: sign in with Authentik — fill in the OIDC_* lines of .env
docker compose up -d
Windows · PowerShell
mkdir kassenknoten; cd kassenknoten
curl.exe -LO https://github.com/jankln/KassenKnoten/releases/latest/download/docker-compose.yml
curl.exe -L -o .env https://github.com/jankln/KassenKnoten/releases/latest/download/env.example
# a session secret, appended to .env
docker run --rm ghcr.io/jankln/kassenknoten:latest `
node scripts/session-secret.ts | Add-Content .env
# your household password, hashed — paste the printed line into .env (notepad .env)
docker run -it --rm ghcr.io/jankln/kassenknoten:latest `
node scripts/hash-password.ts
docker compose up -d
Windows needs
Docker Desktop
with WSL 2. Then open http://127.0.0.1:3000 — a
three-step wizard sets up the household. For access from outside the machine,
put a reverse proxy with TLS in front.
