Welcome to Ziptax

Sales tax in the U.S. is messy. Ziptax isn’t.

12,000+

U.S. tax jurisdictions

80,000+

geographic boundaries

50 states + Canada

covered out of the box

Query by address, lat/lng, or ZIP and get back door-level accurate rates adjusted for unincorporated areas, special districts, and origin-vs-destination sourcing rules. Rates update themselves. No tables to maintain, no overnight syncs.

Choose your path

Recommended

Language SDKs

Idiomatic Go, Python, and Node.js clients with typed models, built-in retries, and full support for every Ziptax feature, including product rules, Canadian rates, and historical lookups.

REST API

Hit /request/v60 directly from any language. Simple X-API-Key auth, predictable JSON responses, versioned endpoints from v10 to v60.

Agents & LLMs

Plug Ziptax into Claude, Cursor, Devin, or any MCP-compatible agent. Installable Claude Skill, hosted MCP server, and a machine-readable OpenAPI spec.

Why Ziptax

Nationwide Coverage

Sales tax rates for every U.S. address and jurisdiction across all 50 states, plus Canadian rates on supported plans.

Real-Time Lookups

Fast, reliable responses on every request. No batch jobs, no overnight syncs.

Address or Coordinates

Query by free-form street address, latitude/longitude pair, or postal code.

Simple Auth

API key via header or query parameter. No OAuth dance required.

Product Codes

Optional per-item Taxability Information Codes (TICs) for precise product-level tax calculations.

Developer-First

OpenAPI 3 spec, predictable JSON responses, language SDKs, and an MCP server for AI agents.

Authentication

Ziptax supports two ways to supply your API key. Pick whichever fits your client:

Header (recommended): send X-API-Key: YOUR_API_KEY
Query parameter: pass key=YOUR_API_KEY on the request URL

Don’t have a key yet? Create a free account at platform.zip.tax.

Quick example

$ curl -H "X-API-Key: YOUR_API_KEY" \
>   "https://api.zip-tax.com/request/v60?address=200+Spectrum+Center+Dr+Irvine+CA"

Want a guided walkthrough instead? The Quickstart gets you from signup to your first SDK call in five minutes.

Where to next

Language SDKs

Idiomatic Go, Python, and Node clients for the Ziptax API.

REST API Guides

Step-by-step walkthroughs for lookups by address, coordinates, or postal code.

Agents & LLMs

MCP server, Claude Skill, and OpenAPI resources for AI integrations.

API Reference

Explore every endpoint, parameter, and response schema.

Pricing & support

See zip.tax/pricing for plan options. Need help? Reach us at support@zip.tax.