How to prepare documentation for your crypto tax advisor

If you hire a tax advisor specialized in cryptocurrencies, you need to bring them all the relevant information. The quality of your statement depends directly on the quality of the data you provide. Here you have the complete checklist.

Why documentation is crucial

A crypto tax advisor is not a magician: he cannot guess your operations. You need:

1. All exchanges where you operated.
2. All self-custody wallets you used.
3. All DeFi protocols you interacted with.
4. Any other source of crypto (mining, airdrops, staking, etc.).

If you forget an exchange or wallet, the FIFO calculation may be completely wrong.

Step 1: Inventory of exchanges and platforms

Make a list of ALL the exchanges you used in the fiscal year:

• ☐ CEX Exchanges: Binance, Coinbase, Kraken, Bitpanda, Bit2Me, Bybit, OKX, Kucoin...
• ☐ Staking/earn exchange: Nexo, Crypto.com, Coinbase Earn...
• ☐ DeFi Platforms: Uniswap, Aave, Compound, Curve...
• ☐ NFT platforms: OpenSea, Blur, Magic Eden...
• ☐ Gaming/P2E: Axie Infinity, The Sandbox...

For each exchange: Export the CSV or transaction report for the fiscal year (and all previous years if this is your first time).

Step 2: Export the CSVs of each exchange

Binance

• Order History: Account → Order Center → Transaction History → Export.
• Deposit/withdrawal history: Portfolio → Transaction history.
• Binance Earn: Reward history in the Earn section.

Coinbase

• "Reports" on the web → "Tax returns" → Export CSV.
• If you have Coinbase Pro (now Advanced Trade): separate history.

Kraken

• History → Export → Select date range → Mark all categories.

Bit2Me

• Similar: User Panel → History → Export.

Other platforms

• Search the exchange documentation: "export transactions", "tax report", "CSV download".

Step 3: Self-custody wallets

If you have Ledger, MetaMask or another wallet:

Simple method (API key / public wallet)

• Provide the advisor with the public address of each wallet (the one that starts with 0x... in Ethereum, bc1... in Bitcoin, etc.).
• The advisor can use tools to analyze on-chain history.
• NEVER share your seed phrase or private key.

Alternative method (manual CSV)

• Use Etherscan to export your Ethereum wallet history.
• Use blockchain.com for Bitcoin.
• For other chains: their respective browsers.

Step 4: Staking and DeFi information

For each DeFi protocol used, it provides:

• Staking/Earn: Export reward history if the protocol allows it.
• Airdrops received: List of tokens received, dates and approximate prices.
• Mining: Pool history (Ethermine, F2Pool, etc.) with payment export.

Step 5: Documentation of special situations

If you had any of these situations:

• ☐ ICO/IDO/IEO: Participation contract, confirmation email, transactions.
• ☐ NFTs bought/sold: History of OpenSea or the platform.
• ☐ Exchange bankruptcy: Balance captures, administrator emails.
• ☐ Hack or loss: Police report, on-chain transactions.
• ☐ Donations or inheritances: Notarial documents.

Step 6: Consolidation Tool

To make the advisor's job easier, consider using a pre-processing tool:

• Koinly/Blockpit: Imports all CSVs and generates a consolidated report.
• CoinTracker: Similar.
• Provides the advisor with both the original CSVs and the tool report.

Additional information needed

• DNI / NIE: Your tax identification.
• Fiscal year: What year are you going to declare? Just this year or previous years too?
• Tax residence: Have you lived in Spain all year? Do you have residence in any specific CCAA?
• Other sources of income: Do you have a payroll? Are you self-employed? Do you have bank accounts abroad?

What you should NOT do

• You don't have to calculate the FIFO manually (that's what the advisor is for).
• You don't have to know the exact tax rates.
• You don't have to know if something is a general or savings basis (the advisor determines this).

Your job = provide complete and organized data.

Warning signs: information you should not forget

• First year declaring crypto: you need the complete history from the beginning (even previous years).
• If you used exchanges that no longer exist: look for screenshots, emails, any trace.
• If you received crypto as payment for work: indicate dates, amounts and payer.

Updated: April 2026 | Fiscal year: 2025