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TaxMaxi is open-source crypto tax infrastructure built for developers. Rather than exporting CSVs and importing them into a consumer tax tool, you connect TaxMaxi to your exchange or wallet and call an API to receive structured, jurisdiction-aware tax data. TaxMaxi handles transaction normalization, FIFO capital gains calculation, and income classification — so your application gets clean numbers instead of raw ledger entries. The first supported jurisdiction is Germany, with Coinbase as the first supported exchange.

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What you can build with TaxMaxi

TaxMaxi exposes three integration surfaces:
  • REST API — call endpoints directly to create sources, trigger syncs, and retrieve tax summaries. The base URL is https://api.taxmaxi.com and the OpenAPI spec is available at https://api.taxmaxi.com/openapi.json.
  • JavaScript SDK — a typed Effect-based client that wraps the REST API. Install it from npm and authenticate with a Bearer token.
  • CLI — the tax command runs the full Coinbase workflow from your terminal. Install it globally with npm install -g tax and run tax coinbase to connect, sync, and calculate taxes in one step.

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Who TaxMaxi is for

TaxMaxi is designed for teams and individuals who need tax data as structured output, not a PDF:
  • Fintechs and exchanges that need to surface tax liability data inside their own product
  • Neobanks and wallets that want to offer tax reporting as a feature
  • AI agents that require deterministic tax logic as part of a broader financial workflow
  • Developers who want to automate crypto tax calculation without manual tools

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Supported integrations

AreaSupport
JurisdictionGermany (FIFO capital gains + income)
ExchangeCoinbase (via OAuth)
OnchainAny wallet address (Solana)

Quickstart

Make your first API call and retrieve a tax summary in minutes.

Authentication

Register, log in, and attach a Bearer token to your requests.

API reference

Browse the full OpenAPI specification for all endpoints.

CLI

Run the full Coinbase workflow from your terminal with the tax command.