Ziptax Sales Tax API

For clean Markdown of any page, append .md to the page URL. For a complete documentation index, see https://docs.zip.tax/llms.txt. For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.zip.tax/_mcp/server.

MCP Server

The Ziptax MCP Server gives AI agents and LLM-powered applications direct access to real-time U.S. and Canadian sales tax data. MCP is an open standard that lets AI applications securely connect to external tools and data sources. Once connected, your agent can:

• Look up sales and use tax rates by postal code, street address, or geographic coordinates.
• Retrieve jurisdiction-level tax breakdowns (state, county, city, and district).
• Query account usage metrics and quota information.

You'll need a valid Ziptax API key. Create a free account at platform.zip.tax.

Connection details

Base URL	https://mcp.zip-tax.com/
Method	POST
Transport	Streamable HTTP (most clients call this HTTP)

Authentication

Every request must include a valid API key sent as an HTTP header. Two header methods are supported.

X-API-KEY header (recommended)

X-API-KEY: your-api-key

Authorization header

Authorization: Bearer your-api-key

If both are present, the X-API-KEY header takes priority. Do not pass your API key as a URL parameter; keys in URLs can end up in logs.

Tools

The server exposes two tools.

lookup_tax_rate

Look up sales and use tax rates for a U.S. or Canadian location. Provide a full street address for door-level precision, or a lat/lng pair for a geographic point lookup. Returns tax rates broken down by jurisdiction (state, county, city, district).

Parameters

Provide either address for a door-level lookup, or lat and lng for a geographic point lookup. The input schema declares this requirement as an anyOf constraint.

Example response

The tool response mirrors the Ziptax REST API by Address response:

{
  "metadata": {
    "version": "v60",
    "response": {
      "code": 100,
      "name": "RESPONSE_CODE_SUCCESS",
      "message": "Successful API Request.",
      "definition": "http://api.zip-tax.com/request/v60/schema"
    }
  },
  "baseRates": [
    {
      "rate": 0.0725,
      "jurType": "US_STATE_SALES_TAX",
      "jurName": "CA",
      "jurDescription": "US State Sales Tax",
      "jurTaxCode": "06"
    },
    {
      "rate": 0.005,
      "jurType": "US_COUNTY_SALES_TAX",
      "jurName": "ORANGE",
      "jurDescription": "US County Sales Tax",
      "jurTaxCode": "30"
    }
  ],
  "taxSummaries": [
    {
      "rate": 0.0775,
      "taxType": "SALES_TAX",
      "summaryName": "Total Base Sales Tax",
      "displayRates": [
        { "name": "Total Rate", "rate": 0.0775 }
      ]
    }
  ],
  "addressDetail": {
    "normalizedAddress": "200 Spectrum Center Dr, Irvine, CA 92618-5003, United States",
    "incorporated": "true",
    "geoLat": 33.65253,
    "geoLng": -117.74794
  }
}

get_account_metrics

Retrieve account usage metrics and quota information for your Ziptax account. Returns current request counts, limits, and entitlements. Takes no parameters.

Example use cases

Once connected, ask your agent things like:

• "What's the sales tax rate for ZIP code 90210?"
• "What's the combined sales tax rate at 200 Spectrum Center Dr, Irvine, CA?"
• "What's the sales tax rate for Canadian postal code M5V 2T6 in Toronto, Ontario?"
• "What was the sales tax rate in Nashville, TN (37203) in January of this year?"
• "How many API requests are left on my Ziptax plan this month?"

Client configuration

Below are configuration examples for connecting popular MCP clients to the Ziptax MCP Server. Replace your_api_key with your Ziptax API key from platform.zip.tax.

Claude Desktop

Add this block to your claude_desktop_config.json:

{
  "mcpServers": {
    "ziptax": {
      "type": "http",
      "url": "https://mcp.zip-tax.com/",
      "headers": {
        "X-API-KEY": "your_api_key"
      }
    }
  }
}

Cursor

Navigate to Settings → MCP and add a new server with:

• Name: Ziptax MCP Server
• Type: HTTP
• URL: https://mcp.zip-tax.com/
• Headers: X-API-KEY: your_api_key

Devin

In Devin, add the Ziptax MCP integration from the MCP Marketplace, or configure it manually under Settings → MCP Marketplace → Add Your Own:

{
  "mcpServers": {
    "ziptax-sales-tax-api": {
      "transport": "shttp",
      "url": "https://mcp.zip-tax.com/",
      "headers": {
        "X-API-KEY": "$ZIPTAX_API_KEY"
      }
    }
  }
}

Store your API key as a secret named ZIPTAX_API_KEY in Devin's Secrets Manager.

Generic MCP client

Any MCP client that supports Streamable HTTP transport can connect:

• Name: Ziptax MCP Server
• Type: HTTP
• URL: https://mcp.zip-tax.com/
• Headers: X-API-KEY: your_api_key

Error handling

When a request fails, the MCP Server returns an error message in the tool result. For the full list of API response codes, see the Response Codes reference.