BTC Tax Tool Web – The Guide

From CSV export to tax office report — in 5 minutes, entirely in your browser

"Your transaction data never leaves your machine. No upload, no account, no tracking — the entire calculation runs locally in your browser."

Step 0: What you need

Just your CSV exports. Every broker and the BitBox app offer an export — downloading once a year is enough:

Purchases without a CSV (Robosats, cash, P2P) or from brokers without a dedicated parser go into a simple manual_buys.csv — details below.

Step 1: Load your files

Open your access link. Drag all CSV files into the dashed zone at once — or click it and select the files. Order does not matter, file names do not matter: the app detects every broker automatically from the file contents.

The start view: simply drag your CSV files into the dashed zone.

Step 2: Check detection — and mark noKYC wallets

After loading, the table shows each file with its detected type. Entries marked orange are noKYC sources — they stay strictly separated from the tax office report:

All files detected — Bisq and manual purchases automatically flagged as noKYC (orange).

If a file is not recognized, the calculation stays locked until you pick a type manually or set the file to "Ignorieren" (ignore) — so an incomplete report can never happen silently. Your broker missing entirely? Send the CSV header line (no real data) to kontakt@alien-investor.org — parsers are added continuously, and as a customer you get new brokers instantly, nothing to install.

Step 3: Compute the report

One click on "Report berechnen" (compute report). On the very first run the app loads its Python environment into the browser — that takes a few seconds once, afterwards it is fast. The system log shows every step:

The system log: every file, every transaction, full transparency.

Step 4: Understanding the results

For every tax year you get several documents, switchable via tabs:

Year tabs on top, document tabs below — here the 2024 tax report.

Step 5: noKYC internal — for your eyes only

Bisq purchases, manual P2P purchases and noKYC wallets end up in a separate internal document with its own FiFo pool. It starts with an unmissable warning:

The red banner says it all: this file is for your own bookkeeping only.

Important: the separation serves your privacy and clean internal bookkeeping — gains from noKYC sales are still taxable and belong in your tax return. The document gives you FiFo matching, holding periods and gains for exactly that purpose.

Step 6: Download and file

Use the download buttons to grab each document individually or all at once. You file two things with the tax office:

• the Steuernachweis (steuernachweis_YEAR.txt), and
• your brokers' original CSVs as proof the purchases are real.

The statement shows under "Quelle" (source) exactly which broker supplied which lot — every sale is fully traceable.

Frequently asked questions

What about purchases in CHF or USD (Swissquote, Pocket)?

The app converts them automatically using the historical daily rate. For that, your browser (only if needed) queries the open exchange-rate API frankfurter.app — dates yes, amounts no.

My broker is missing — what now?

Interim solution: enter the purchases in manual_buys.csv (date,btc_amount,eur_amount,note,kyc — for KYC brokers like Coinbase set the kyc column to ja). And in parallel send the CSV header line to kontakt@alien-investor.org — new parsers usually land within days.

Is the demo the same as the full version?

Yes — same calculation engine, same interface. In the demo you can download the sample data as a ZIP and drag the files in yourself — exactly like you will later with your real files. Or use the one-click "Demo-Daten laden" button. Your own files are only accepted by the full version with an access link:

The demo: drag the sample data just like in the full version — your own files need the access link.