Kintsugi API documentation
Build sales tax into your product. Calculate tax at checkout, sync transactions and customers, and manage nexus, registrations, and filings, all through the Kintsugi API.
Explore the docs
API reference
Every endpoint, with its parameters, request samples, and example responses, generated from our OpenAPI specs.
Getting started
Set up your account, create an API key, and make your first authenticated request.
Guides
How sales tax works, and how to integrate Kintsugi from checkout to filing.
API Lab
Interactive recipes that walk through common workflows, one call at a time.
API changelog
Every change to the API, newest first, with breaking changes marked.
Partner API
Portfolio and partner endpoints for platforms and marketplaces. Partner access required.
Popular endpoints
API versions
The docs cover v1 and the Tenanted API, release 2026-07-21. Switch between them with the version picker in any sidebar, or start from the Tenanted API reference.