Free and open source · Windows, macOS, Linux
Multi-currency personal finance that stays on your machine.
Koinkat is a desktop app for tracking accounts, budgets, and split expenses across currencies. It connects to European banks over PSD2 or works fully manually, and it stores everything in a SQLite database on your own computer. No account, no server, no telemetry.
Version 0.1.0 · Koinkat_0.1.0_x64-setup.exe · Koinkat_0.1.0_aarch64.dmg (Apple Silicon) · Koinkat_0.1.0_amd64.AppImage · deb, rpm and all files on the releases page
The installers are not code-signed, so Windows and macOS will show an unknown-developer warning. That is expected: why, and how to proceed.
Local-first
How Koinkat handles your data
Your financial data lives in a SQLite database file on your own computer. There is no Koinkat server, no account with us, no sign-up, no telemetry, and no analytics. Nobody involved in this project can see your data.
"Local-first" does not mean the app never touches the internet. This is the complete list of outbound connections, verifiable in the source:
Nothing else phones home
Like every internet request, these servers see your IP address. Beyond this list there is nothing: no update pings, no crash reporting, no tracking. The app's content-security policy blocks requests to any other host, so a bug or a compromised dependency could not quietly phone home.
One honest caveat
The database is not encrypted at rest: anyone with access to your OS user account can read it, so use disk encryption (BitLocker, FileVault, LUKS) if that matters to you. Your Enable Banking private key is kept in the OS credential store, not in the database. Details in the security model.
Features
What it does
Accounts and net worth
Track accounts across currencies. Net worth converts to your preferred currency at today's rates, and every transaction stores the FX rate it was recorded at, so balances stay reproducible.
Bank sync over PSD2
Connect European banks through Enable Banking, read-only: it sees the balances and transactions you authorize and can never move money. Manual accounts work without any bank at all.
Review inbox and rules
Imported transactions land in Review with a suggested category: your rules first, an MCC fallback behind them. Confirming teaches the engine, and most soon arrive pre-sorted.
Split expenses
Track split expenses and who still owes what, including repayments via PayPal or cash, outside your bank accounts. Fees are recorded as separate linked transactions.
Budgets
Recurring monthly budgets plus one-off envelope events, with multi-currency math. The Dashboard shows pace: what is spent, and what is safe per day until month end.
Workspaces
Each workspace is fully isolated, with its own accounts, categories, budgets, and bank links. Start manual, then add a bank-linked workspace whenever you are ready.
Your bank
PSD2, read-only
Sync
Within PSD2 rate limits
Review inbox
Suggested category
Categorized
Rules learn from you
Each sync pulls new transactions into Review with a suggested category. Confirming them teaches Koinkat your categories.
The screens
Rendered in HTML with the app's own styles, not screenshots. Sample data.
Multi-currency
Built for money that crosses currencies
Salary in one currency, rent in another, a card in a third. Koinkat treats that as the normal case: accounts keep their native currency, totals convert to yours, and budgets do the conversion math per period.
One preferred currency. Pick it per workspace; the Dashboard converts every balance into it at the day's rates.
Rates recorded, not guessed. Every transaction stores the exchange rate it was recorded at, so historical balances stay reproducible.
Decimal money math. Amounts are handled with big.js. IEEE 754 floats never touch monetary values.
Converted at daily rates
1 EUR = 7.4604 DKK
1 GBP = 1.1554 EUR
Sample data, public daily rates.
Get started
Three steps
Install
Download the installer for your system. It is not code-signed, so Windows and macOS will warn about an unknown developer; the install guide shows the exact clicks to proceed. Prefer to run what you can read? Build from source instead.
Create a workspace
On first launch you enter a name. That is the whole "account": a label on your machine, not a login to anything. A Manual workspace works immediately, no bank required.
Link a bank, if you want
Register your own free Enable Banking application first, a one-time job of roughly 15 to 20 minutes walked through by the in-app setup guide and the README. Then pick your bank and approve read access on the bank's own website.
Before you install
Limitations, stated plainly
The install guide has the exact warning-bypass clicks per OS. v0.1.0 is the first public release; if something does not behave as documented, open an issue.