100% in your browser
capi.tax runs entirely on your own computer. Your broker export and your transaction data never travel to a server, and there is no account to create. Everything that happens with your figures happens in the browser tab in front of you.
Nothing is uploaded
When you select your CSV file, the browser reads it directly from your computer. It is not sent anywhere. The whole calculation — currency conversion, FIFO matching, the tax summary — is performed locally and shown back to you on the same page.
Because your data never leaves your device, there is no copy of it on any server, no database that could be breached, and nothing for us to store, share, or sell. We simply never receive it.
It works offline
The first time you open capi.tax, your browser downloads the application itself: the page and the calculation engine. After that, the calculation runs without an internet connection. You can disconnect from the network, load your file, and still get your full result. The only thing that needs the internet is fetching official Deutsche Bundesbank exchange rates, and those are cached once retrieved.
Your data is cleared when you leave
Your transactions live only in the browser's memory while you work. When you close the tab or navigate away, that memory is released and the data is gone. There is nothing to delete afterwards, because nothing was kept.
The clock in the header
For your protection, the session also clears itself after 15 minutes of inactivity. On the results page you will see a countdown for this in the top right. It runs while you read, and resets as soon as you do something again.
- In the final minute the display changes colour — your warning.
- The arrow button next to it puts the clock back to the start if you need longer.
- Hover the countdown and it becomes Delete results — the way to discard everything at once, deliberately.
When the time runs out, your data is removed rather than sitting open on screen — useful on a shared machine, or when you have to step away.
Privacy mode for the screen
Next to the countdown sits an eye icon. It blurs every amount on the results page — the structure stays visible, the numbers do not. Made for the moment when someone is looking over your shoulder, for a screenshot, or for a screen share.
The mode affects the display only; the calculation is unchanged, and the export contains the real figures. Your browser remembers the choice locally for next time — what is stored is the setting alone, never any of your numbers.
A practical note
Since nothing is stored, your results are not kept for you between visits. If you want to keep a copy, export your report before you close the page. To move your work to another device, export it and open it there — there is no cloud sync, by design.
See it for yourself
You can verify all of this. Open your browser's developer tools, switch to the network tab, and process a file. You will see the application and exchange rates load, but no upload of your data. Or load the page once, disconnect from the internet, and confirm the calculation still runs.