dTax

The only complete TypeScript crypto tax engine on npm

English · 简体中文 · 繁體中文 · Español · 日本語 · 한국어 · Português

---

23 exchange parsers | FIFO / LIFO / HIFO / Specific ID | Form 8949 + Schedule D | Wash sale detection | What-if simulator

Install

npm install @dtax/tax-engine

Quick Example

import {
  parseCsv,
  CostBasisCalculator,
  generateForm8949,
} from "@dtax/tax-engine";

// 1. Parse any exchange CSV (auto-detects format)
const { lots, events } = parseCsv(csvString);

// 2. Calculate gains/losses
const calc = new CostBasisCalculator("FIFO");
calc.addLots(lots);
const results = events.map((e) => calc.calculate(e));

// 3. Generate IRS Form 8949
const report = generateForm8949(results);

CLI

Calculate taxes from the command line without writing any code:

npx @dtax/cli calculate trades.csv --method FIFO
npx @dtax/cli calculate trades.csv --method LIFO --year 2025 --json
npx @dtax/cli calculate coinbase.csv binance.csv --method HIFO

Install globally for repeated use:

npm install -g @dtax/cli
dtax calculate trades.csv --method FIFO --form8949 report.csv
dtax calculate trades.csv --schedule-d --include-wash-sales

Supported Exchanges (23 Parsers)

All parsers auto-detect the CSV format. No configuration required.

Category	Exchanges
Major	Coinbase, Binance, Binance US, Kraken, Gemini
Global	KuCoin, OKX, Bybit, Gate.io, Bitget, MEXC, HTX (Huobi)
Other	Crypto.com, Bitfinex, Poloniex
On-chain	Etherscan (ETH + ERC-20 + BSC/Polygon/Avalanche/Fantom), Solscan (SOL + SPL + DeFi)
Migration	Koinly, CoinTracker, Cryptact (import from competitors)
Fallback	Generic CSV (map your own columns)

Features

• 4 cost basis methods -- FIFO, LIFO, HIFO, Specific ID (IRS-compliant)
• Form 8949 -- CSV, PDF, and TXF (TurboTax) export with Box A-F classification
• Schedule D -- Part I/II aggregation, $3,000 loss limit, carryover calculation
• Wash sale detection -- 30-day window, partial disallowance, Form 8949 code W
• What-if simulator -- Preview tax impact before selling (simulateSale())
• Method comparison -- Find the optimal method across FIFO/LIFO/HIFO (compareAllMethods())
• DeFi + NFT support -- LP deposits/withdrawals, staking, wraps, bridges, 12 DeFi tx types
• 1099-DA reconciliation -- 3-phase matching against broker-reported data
• Portfolio analysis -- Holdings aggregation, unrealized P&L, tax-loss harvesting opportunities
• Wallet-siloed accounting -- Strict per-wallet cost basis isolation
• Internal transfer matching -- Auto-detect transfers between your own wallets

Comparison with Alternatives

Feature	dTax	Rotki	RP2
Language	TypeScript	Python	Python
npm installable	Yes	No	No
Exchange parsers	23	15	8
Cost basis methods	4	3	3
Form 8949 PDF	Yes	No	No
TurboTax TXF export	Yes	No	No
Schedule D generation	Yes	No	No
Wash sale detection	Yes	Yes	No
What-if simulator	Yes	No	No
Method comparison	Yes	No	No
DeFi/NFT tx types	12	8	4
1099-DA reconciliation	Yes	No	No
Competitor CSV import	Yes	No	No
CLI tool	Yes	Yes	Yes
Browser/Node.js	Both	Desktop	CLI only

Packages

Package	Description
@dtax/tax-engine	Core calculation engine, parsers, reports
@dtax/cli	Command-line interface
@dtax/shared-types	TypeScript type definitions

API Highlights

// Cost basis calculation
import { calculateFIFO, calculateLIFO, calculateHIFO } from "@dtax/tax-engine";

// Reports
import {
  generateForm8949,
  form8949ToCsv,
  generateForm8949Pdf,
} from "@dtax/tax-engine";
import { generateScheduleD } from "@dtax/tax-engine";
import { form8949ToTxf } from "@dtax/tax-engine"; // TurboTax

// Analysis
import { detectWashSales } from "@dtax/tax-engine";
import { simulateSale } from "@dtax/tax-engine"; // what-if
import { compareAllMethods } from "@dtax/tax-engine"; // optimizer
import { analyzeHoldings } from "@dtax/tax-engine"; // portfolio

// Parsers (auto-detect or use individually)
import { parseCsv, detectCsvFormat } from "@dtax/tax-engine";

Contributing

Contributions welcome. See CONTRIBUTING.md for guidelines.

# Prerequisites: Node.js >= 20, pnpm >= 9
git clone https://github.com/dTaxLab/dtax.git && cd dtax
pnpm install
pnpm test        # 800+ tests across all packages
pnpm build       # build all packages

License

All packages in this repository are licensed under AGPL-3.0.

This means you can use dTax freely in your projects. If you modify the source and distribute it (including as a network service), you must release your modifications under AGPL-3.0.

For commercial licensing inquiries: getdtax.com

Links

• Website: getdtax.com
• Issues: GitHub Issues
• Discussions: GitHub Discussions