Ziptax Sales Tax API

What Ziptax Sales Tax API MCP server does

The Ziptax Sales Tax API MCP server gives MCP-compatible clients access to the Ziptax API v60 through a hosted endpoint at https://mcp.zip-tax.com/. It supports sales and use tax lookups for locations in the United States and Canada, plus account-level usage checks.

Its two tools are read-only. lookup_tax_rate returns rates separated by jurisdiction, including state or province, county, city, and district data. get_account_metrics reports request counts, plan limits, usage percentage, and whether the API key is active.

How it works

Clients send POST requests using the Streamable HTTP transport. Sessions are stateless, so each request carries the authentication header and tool input needed for processing. The MCP server forwards supported requests to the Ziptax API and returns the API v60 response as formatted JSON text, or unchanged XML when the lookup uses format: "xml".

For lookup_tax_rate, provide a full street address, a matching lat and lng pair, or a postal code. Addresses and coordinates support door-level precision. Postal codes are less precise and may return every rate overlapping the area rather than one authoritative rate. The tool can also accept state, city, county, country, historical period, adjustment, taxability code, Tennessee single-article-tax item total, and response-format parameters.

Historical queries use YYYYMM and are limited to the previous 12 months. Canadian requests require the CA country code and a Pro or Enterprise plan. Historical data and product taxability codes also require Pro or Enterprise access.

Setup and configuration

The Ziptax Sales Tax API MCP server requires a valid Ziptax API key. Create or manage a key at https://platform.zip.tax, then send it in the X-API-KEY header. A Bearer token in the Authorization header is also supported; if both headers are present, X-API-KEY takes precedence. Do not put the key in a URL because URLs can be recorded in logs.

For Claude Desktop, configure an HTTP MCP server with the endpoint and an X-API-KEY header. Claude Code can be configured with its HTTP transport command and the same header. Cursor uses its MCP settings with the server URL and header. Devin can store the key as ZIPTAX_API_KEY in Secrets Manager and reference it in its MCP configuration. Other clients must support Streamable HTTP.

Tools and capabilities

• lookup_tax_rate: Retrieve US or Canadian sales and use tax rates by address, coordinates, or postal code.
• get_account_metrics: Retrieve request usage, quota, percentage used, and account status without parameters.
• Return jurisdiction-level rate breakdowns for state, county, city, and district authorities.
• Request historical rates, where the account plan and 12-month lookback limit permit it.
• Request JSON by default or XML using the lookup format option.

Limitations and notes

The Ziptax Sales Tax API MCP server requires authentication for both tools. A lookup must include an address, both latitude and longitude, or a postal code. Input types matter: postal codes should be sent as strings so leading zeroes are preserved, while selected numeric fields may accept JSON numbers.

Postal-code results are inherently less precise and do not select a single authoritative rate for an area or adjust for unincorporated locations. The adjustment: "auto" option enables state-specific unincorporated-area adjustments. The server returns tool errors with isError: true and a text message when authentication, validation, upstream API access, or the 15-second request timeout causes a failure.