# Crypto Accounting & Audit

Accounting software can add up the transactions it is given. What it cannot do is prove it was given all of them — and completeness, not arithmetic, is what an auditor actually tests. An extended public key fixes the address set, and syncing fixes the history: derive every address the key can produce, pull each one's full transaction record, and you have a ledger whose boundary you can demonstrate rather than assert.

## Some of the features you can use

### One key defines the address set

Derive every receiving and change address an account can produce from its extended public key — a public key, never a private one. The set is complete by construction, so there is no question of an address having been missed.

### Full history, not the recent window

Sync an address and read its entire transaction record, not just the last fortnight. Coin transfers, token transfers and EVM internal transactions all come back through the same endpoints, so a contract-mediated movement is not silently absent from the books.

### Reconcile against the chain, continuously

Subscribe to confirmed transactions on the addresses you track and check your own ledger against what actually settled — the same day, rather than at the period close when the discrepancy is expensive to unpick.

### An audit trail that does not depend on us

Every figure traces to a transaction hash on a public chain. A reviewer can verify it independently, and your records stay yours whether or not you keep using the API.

## What is yours, not ours

Cost basis, tax lots, jurisdiction rules and period valuation stay on your side. Crypto APIs supplies the transaction record and current exchange rates; it does not publish a price-history API, so historical valuation needs your own source.

If you are building a tax product rather than reconciling books, see [Crypto Taxes & Accounting](/use-cases/crypto-taxes).

## Related

- [Chains and tokens](/chains-and-tokens) · [Use cases](/use-cases) · [Developer portal](https://developers.cryptoapis.io/)

## How to reconcile crypto in your books

1. **Map wallets to accounts** — Register each wallet's addresses so every movement has a ledger home.
2. **Capture every movement** — Read full history including internal transactions, which plain transfer lists miss.
3. **Value at transaction time** — Pull the rate at each timestamp so the book value matches the moment it moved.
4. **Get notified, not surprised** — Subscribe to webhooks so new activity reaches the ledger as it happens.