How do I find my USPS User ID?

Register for an account at the [**USPS Web Tools registration page**](https://www.usps.com/business/web-tools-apis/welcome.htm). You will receive your User ID via email. Copy and paste it below.

Does it support international tracking?

Yes. The `track_usps_package` tool supports tracking for any valid USPS tracking number, including international shipments originating from or delivered by USPS.

What is the format for address verification?

The API requires an object with line1, city, and state metadata. Standardizing these inputs ensures the most accurate verification from the USPS database.

USPS Developer Portal MCP Server for Claude Desktop 8 tools — connect in under 2 minutes

Name: USPS Developer Portal
Availability: InStock
Author: Vinkius

modelcontextprotocol.io/quickstart/user

Built by Vinkius GDPR 8 Tools IDE

Claude Desktop is Anthropic's native application for interacting with Claude AI models on macOS and Windows. It was the first consumer application to ship with built-in MCP support, making it the reference implementation for the Model Context Protocol standard.

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Vinkius supports streamable HTTP and SSE.

RecommendedModern Approach — Zero Configuration

Vinkius Desktop App

The modern way to manage MCP Servers — no config files, no terminal commands. Install USPS Developer Portal and 2,500+ MCP Servers from a single visual interface.

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Classic Setup·json

{
  "mcpServers": {
    "usps-developer-portal": {
      // Your Vinkius token — get it at cloud.vinkius.com
      "url": "https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp"
    }
  }
}

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* Every MCP server runs on Vinkius-managed infrastructure inside AWS - a purpose-built runtime with per-request V8 isolates, Ed25519 signed audit chains, and sub-40ms cold starts optimized for native MCP execution. See our infrastructure

About USPS Developer Portal MCP Server

Empower your AI agent to orchestrate your entire postal logistics and address auditing workflow with the USPS Developer Portal, the official source for United States Postal Service data. By connecting USPS Web Tools to your agent, you transform complex shipping tasks into a natural conversation. Your agent can instantly verify addresses, audit package tracking statuses, and retrieve ZIP code metadata without you ever touching a shipping portal. Whether you are managing e-commerce deliveries or conducting regional address audits, your agent acts as a real-time logistics consultant, ensuring your data is always verified and precise.

Claude Desktop is the definitive way to connect USPS Developer Portal to your AI workflow. Add the Vinkius Edge URL to your config, restart the app, and Claude immediately exposes all 8 tools in the chat interface — ask a question, Claude calls the right tool, and you see the answer. Zero code, zero context switching.

What you can do

Address Auditing — Standardize and verify United States addresses to ensure your shipping metadata is always grounded in official USPS records.
Advanced Tracking Control — Track real-time package statuses and access granular facility-level tracking events instantly.
ZIP Code & Routing Discovery — Cross-reference ZIP codes with city/state pairs to understand the geographic reach of your logistics.
Domestic & International Rates — Accurately calculate the real-time cost of shipping across various mail classes, weights, and global destinations.
Service Delays & Commitments — Query live delivery commitments by mail class to accurately orchestrate e-commerce fulfillment.

The USPS Developer Portal MCP Server exposes 8 tools through the Vinkius. Connect it to Claude Desktop in under two minutes — no API keys to rotate, no infrastructure to provision, no vendor lock-in. Your configuration, your data, your control.

How to Connect USPS Developer Portal to Claude Desktop via MCP

Follow these steps to integrate the USPS Developer Portal MCP Server with Claude Desktop.

Open Claude Desktop Settings

Go to Settings → Developer → Edit Config to open claude_desktop_config.json

Add the MCP Server

Paste the configuration above into the mcpServers section

Restart Claude Desktop

Close and reopen Claude Desktop to load the new server

Start using USPS Developer Portal

Look for the 🔌 icon in the chat — your 8 tools are now available

Why Use Claude Desktop with the USPS Developer Portal MCP Server

Claude Desktop by Anthropic provides unique advantages when paired with USPS Developer Portal through the Model Context Protocol.

Claude Desktop is the reference MCP client — it was designed alongside the protocol itself, ensuring the most complete and stable MCP implementation available

Zero-code configuration: add a server URL to a JSON file and Claude instantly discovers and exposes all available tools in the chat interface

Claude's extended thinking capability lets it reason through multi-step tool usage, chaining multiple API calls to answer complex questions

Enterprise-grade security with local config storage — your tokens never leave your machine, and connections go directly to the Vinkius Edge network

USPS Developer Portal + Claude Desktop Use Cases

Practical scenarios where Claude Desktop combined with the USPS Developer Portal MCP Server delivers measurable value.

Interactive data exploration: ask Claude to query DNS records, look up WHOIS data, and cross-reference results in a single conversation

Ad-hoc security audits: type a domain name and let Claude enumerate subdomains, check DNS history, and flag configuration anomalies — all through natural language

Executive briefings: generate comprehensive domain intelligence reports by asking Claude to compile findings into a formatted summary

Learning and training: new team members can explore API capabilities conversationally without needing to read documentation

USPS Developer Portal MCP Tools for Claude Desktop (8)

These 8 tools become available when you connect USPS Developer Portal to Claude Desktop via MCP:

calculate_domestic_rate

Calculate USPS domestic shipping rates

calculate_international_rate

Calculate USPS international shipping rates

get_delivery_commitments

Get USPS service delivery commitments and estimates

lookup_usps_city_state

Look up the city and state for a ZIP code

lookup_usps_zip_code

Look up the exact ZIP code for a specific US address

track_usps_package

Track a USPS package using a tracking number

track_usps_package_advanced

Get advanced tracking information for a USPS package

verify_usps_address

Verify and standardize a US address using USPS Web Tools

Example Prompts for USPS Developer Portal in Claude Desktop

Ready-to-use prompts you can give your Claude Desktop agent to start working with USPS Developer Portal immediately.

"Verify address '1600 Pennsylvania Avenue NW, Washington, DC 20500' using USPS."

"Track my package with tracking number '9400100000000000000000'."

"Lookup ZIP code for 'Seattle, WA'."

Troubleshooting USPS Developer Portal MCP Server with Claude Desktop

Common issues when connecting USPS Developer Portal to Claude Desktop through the Vinkius, and how to resolve them.

Server not appearing after restart

Ensure the JSON is valid (no trailing commas). Check the file path: ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\\Claude\\ (Windows).

Authentication error

Verify your Vinkius token is correct. Go to cloud.vinkius.com to regenerate it if needed.

Tools not showing in chat

Click the 🔌 icon at the bottom of the chat input. If it shows 0 tools, the server may still be connecting — wait a few seconds.

USPS Developer Portal + Claude Desktop FAQ

Common questions about integrating USPS Developer Portal MCP Server with Claude Desktop.

How does Claude Desktop discover MCP tools?

When Claude Desktop starts, it reads the claude_desktop_config.json file and connects to each configured MCP server. It calls the tools/list endpoint to fetch the schema for every available tool, then surfaces them as clickable options in the chat interface via the 🔌 icon.

What happens if the MCP server is temporarily unavailable?

Claude Desktop handles disconnections gracefully — if the server is unreachable at startup, the tools simply won't appear. Once the server becomes available again, restarting Claude Desktop will re-establish the connection. There is no timeout penalty or error loop.

Can I connect multiple MCP servers simultaneously?

Yes. You can add as many servers as you need in the mcpServers section of the config file. Each server appears as a separate tool provider, and Claude can use tools from multiple servers in a single conversation turn.

Is there a limit on the number of tools per server?

Claude Desktop can handle hundreds of tools per server. However, for optimal LLM performance, Vinkius servers are designed to expose focused, well-documented tool sets rather than overwhelming the model with too many options.

Does Claude Desktop support Streamable HTTP transport?

Yes. Claude Desktop supports both SSE (Server-Sent Events) and the newer Streamable HTTP transport that Vinkius uses. Simply provide the server URL — Claude auto-negotiates the transport protocol.