Address Validation MCP Servers for AI Agents, Compared

An address validation MCP server gives an AI agent, such as Claude, Cursor or VS Code, a tool it can call to check a postal address. On October 16, 2026 we found seven: sthan.io, Smarty, Informatica, Acuris, Byteplant, a community USPS server and a Pipedream listing for Google Address Validation. They differ in where they run, how many tools they expose, which countries they cover, what you sign up for and what it costs.

Seven address MCP servers side by side

Each row comes from the server's own docs, its package listing and the official MCP registry, all read on October 16, 2026. "stdio" means the server runs on your computer and your AI client starts it. "Remote" means you point your client at a web address and install nothing.

Three things stand out. First, only three of the seven turned up in our searches of the official MCP registry: sthan.io, Byteplant and Acuris. Second, the remote servers (Smarty, Informatica, Acuris) need nothing installed, while sthan.io and Byteplant run on your computer. Third, tool counts range from 0 to 20. Smarty's 20 tools reach well past validation, into property, census and business data, but each tool works only if your Smarty subscription includes a license for the API behind it.

Which servers only pass calls to someone else's API

A server can be the vendor's own front door, or a thin layer over another company's API. The difference matters, because a wrapper inherits the other API's sign-up, limits and price.

The 60-calls-an-hour figure is the USPS default, not a limit of the MCP server itself. USPS says to submit a service request to raise it.

A live tool call, and what the others returned without an account

We did not create an account with any vendor. We installed @sthan/mcp-server 0.1.11 from npm, started it over stdio with a sthan.io key, and sent one MCP tool call for a well-known public address, the White House. This is the exact request our client sent:

{"jsonrpc": "2.0", "id": 3, "method": "tools/call", "params": {"name": "sthan_verify_address", "arguments": {"address": "1600 Pennsylvania Ave NW, Washington, DC 20500"}}}

The tool answered with one text block. This is its content with two internal debugging fields left out; every other field is unchanged:

{
  "inputAddress": "1600 Pennsylvania Ave NW, Washington, DC 20500",
  "fullAddressHash": -8236228518493108000,
  "fullAddressHashString": "-8236228518493108276",
  "fullAddress": "1600 Pennsylvania Ave NW, Washington, DC 20500-0005",
  "addressLine1": "1600 Pennsylvania Ave NW",
  "addressLine2": "Washington, DC 20500-0005",
  "unitType": null,
  "unitNumber": null,
  "city": "Washington",
  "stateCode": "DC",
  "county": "District Of Columbia",
  "zipCode": "20500",
  "zip4": "0005",
  "carrierRoute": "C000",
  "deliveryPoint": "00",
  "checkDigit": "8",
  "cmar": "N",
  "elot": "0002",
  "elotIndicator": "A",
  "recordType": "S",
  "dpvConfirmation": "Y",
  "defaultFlag": null,
  "defaultInd": "E",
  "deliverableStatus": "Confirmed",
  "lastVerifiedDate": "2026-10-08T12:12:17",
  "matchMode": "Speculative",
  "matchTier": "Exact",
  "confidence": 1,
  "matchCode": {
    "houseNumber": "Matched",
    "street": "Matched",
    "unit": "NotApplicable",
    "city": "Matched",
    "state": "Matched",
    "zipCode": "Matched",
    "zip4": "Inferred"
  },
  "footnotes": [],
  "isError": false,
  "errorMessages": []
}

Two internal debugging fields are left out of the response above; everything else is as returned.

What an agent can read from this: deliverableStatus is Confirmed and dpvConfirmation is Y, so the address is deliverable. The ZIP+4 (20500-0005) was added, and matchCode marks it Inferred because we did not type it. The county came back too. To set the server up in your own client, see how to parse messy US addresses with the API, MCP and CLI.

Acuris was the one other server we could reach with no account. Its remote server answered the MCP handshake and listed 9 tools without a key. The same White House call to validate_address came back with an api_key_required error that pointed to its request_trial_key tool for a free trial key.

We did not call request_trial_key, because it signs you up with an email address. Smarty's docs say the initialize step needs no credentials, but on October 16, 2026 its server answered our initialize request with HTTP 401 and {"error":"missing Auth-Id or Authorization header"}. The Byteplant, USPS community and Informatica servers all need a key or an account before they look anything up, and the Pipedream listing had no tools to call.

Which server fits which job

Sources

All pages read October 16, 2026. Live MCP calls made the same day. Details change; check each vendor's page before you choose.

• sthan.io: github.com/sthan-io/mcp-server (README and releases), npm @sthan/mcp-server, Glama listing, sthan.io pricing, and a live tools/call to the server
• Smarty: Smarty MCP Server docs, Smarty MCP Server page and FAQ, and a live initialize request to https://mcp.api.smarty.com/
• Informatica: Address Verification server, Introduction to Informatica MCP servers, Connecting to an Informatica MCP server
• Acuris: Acuris Geo MCP server docs, MCP registry entries, Glama search listing, and live initialize, tools/list and tools/call requests to https://api.acuris-geo.com/mcp
• Byteplant: byteplant-mcp on PyPI (README and release dates), GitHub repository, Address Validator pricing
• USPS community server: github.com/bailur/usps-mcp-server, Glama listing, USPS developer portal, Getting Started, USPS developer FAQ
• Google Address Validation on Pipedream: Pipedream MCP page, Google Address Validation usage and billing
• Official MCP registry searches: sthan, smarty, byteplant, informatica, usps, pipedream, google-address