Crypto Tax Calculator API

Premium crypto tax calculation engine — REST API + MCP server.

Calculate capital gains/losses with FIFO, LIFO, and Average Cost basis methods. Automatic short-term vs long-term classification (365-day threshold). Supports any cryptocurrency (BTC, ETH, SOL, ADA, etc.).

Quick Start

npm install
npm start          # REST API on port 5300
npm run mcp        # MCP server (stdio)

API Endpoints

GET /api/v1/methods

List supported cost basis methods and CSV format.

POST /api/v1/calculate

Calculate taxes from a trade list.

{
  "method": "fifo",
  "trades": [
    { "type": "buy",  "currency": "BTC", "amount": 1.0,  "price_per_unit": 30000, "date": "2025-01-15", "fee": 5 },
    { "type": "sell", "currency": "BTC", "amount": 0.5,  "price_per_unit": 45000, "date": "2025-08-20", "fee": 5 }
  ]
}

POST /api/v1/csv

Parse CSV trade history and calculate.

type,currency,amount,price_per_unit,date,fee
buy,BTC,1.0,30000,2025-01-15,5
sell,BTC,0.5,45000,2025-08-20,5

POST /api/v1/summary

Annual tax summary comparing all methods side by side with lowest-tax recommendation.

MCP Tools

| Tool | Description | |------|-------------| | calculate_crypto_tax | Calculate gains/losses from trade array | | parse_csv_trades | Parse CSV + calculate | | list_tax_methods | List available methods | | annual_tax_summary | Per-year multi-method comparison |

Docker

docker build -t crypto-tax-calculator .
docker run -p 5300:5300 crypto-tax-calculator

Features

• FIFO, LIFO, Average Cost basis methods
• Short-term vs long-term capital gains (365-day threshold)
• Per-disposal breakdown with cost basis, proceeds, gain/loss
• Annual summary by year and by currency
• Lowest-tax method recommendation
• CSV import with flexible column mapping
• Fee-aware calculations
• 8 decimal place precision (crypto-grade)

License

MIT