What gets checked
The check reads machine exports from your exchanges and wallets and reconstructs the chain a compliance desk wants to see: every crypto deposit has to be attributable to a known withdrawal from another exchange or your own wallet. Deposits without a documented source are the classic hole a proof fails on. In addition, the computed balance per exchange and asset is tracked: if it goes negative, the export starts too late and records are missing.
Supported formats
Kraken ledger · Generic CSV (date,venue,type,asset,amount)
For every other source there is a simple generic CSV format with the columns date,venue,type,asset,amount, where type is one of deposit, withdrawal or trade and withdrawals carry a negative sign. More exchange formats will follow.
Frequently asked questions
When does a bank demand proof of source of funds?
Under German anti-money-laundering law banks review conspicuous inflows; 10,000 euros is the commonly cited threshold, but proof can be demanded below it too. Notaries in property purchases and exchanges themselves ask as well.
Are screenshots of my accounts enough?
No. A screenshot proves a balance, not an origin. What is demanded are machine-generated full exports over the entire period and a traceable link between bank account, exchange account and wallet.
What do I do about a gap the check finds?
Every gap names concretely which document is missing: usually the full export of another source or an earlier period. Gaps that can no longer be closed, for instance because an exchange no longer exists, should be documented and, in doubt, handled with legal counsel before the bank asks.
Couldn't ChatGPT do this too?
A language model could attempt the analysis - but you would have to upload your complete financial history to a US provider, the result would differ on every run, and a chat transcript is worth nothing to a bank. This check demonstrably transmits nothing (it works offline), computes deterministically, and produces a file with checksums any recipient can verify with standard tools. The difference is not the analysis; it is the verifiable result.
Further reading
Crypto source-of-funds checks: what German banks demand · The file as an open format · The booking engine's rulebook · Stablecoin accounting in Germany: the guide
This tool structures your own records and is no substitute for legal advice in a specific case. Whether a proof satisfies a particular bank is decided by its compliance department; frozen accounts or gaps that cannot be closed belong with a specialised law firm.