LawDiver for Tax · Free on the web

Federal tax law, by year, with status

Read the Internal Revenue Code and Treasury regulations as of any held edition. Open IRS guidance with effect and judicial history. Check cites. Look up forms and treaties. The web product is free for now.

Open LawDiver TaxTax API docs

Use it on the web

No API key in the browser. Jump straight into the tool:

What you get

Point-in-time Code and regs, IRS guidance with status, and a dedicated Tax API.

Code and regs by year

Open any held IRC or Treas. Reg. edition. Put another year beside it at 50/50, or shift-click for a redline. Make main promotes the side panel.

IRS guidance with status

Rev. Ruls, Rev. Procs, notices, written determinations, and more — with effect-on-other-documents status and judicial history.

Forms and treaties

Form and instruction revisions by tax year, plus income-tax treaty articles.

Tax API

Programmatic search, law, guidance, check, forms, treaties, and what’s new. Separate ld_tax_ keys on a regular account.

From browser to API

  1. 1

    Use the free web

    Open /tax and research without creating a key.

  2. 2

    Create a regular account

    Sign up when you want programmatic access. Same accounts as caselaw.

  3. 3

    Mint an ld_tax_ key

    Account → API Keys → Tax API. Caselaw ld_live_ keys do not open /api/v1/tax/*.

Claude and OpenAI

Tax MCP at /mcp/tax works today with an ld_tax_ key. Claude.ai and OpenAI directory connectors for Tax are coming soon — we will list them here when the OAuth clients and directory listings ship.

Developers

Full endpoint reference: LawDiver for Tax API. Integration starter: github.com/lawdiver/LawDiver-tax-api.

LawDiver for Tax — IRC, Treas. Regs, IRS Guidance | LawDiver