Lob MCP for AI. Send physical mail—from checks to postcards.
Gemini Works with every AI agent you already use
…and any MCP-compatible client
How this MCP server connects to your AI agent
Lob MCP Server lets you manage direct mail programs through natural conversation. Send physical letters (PDF/HTML), postcards, and checks by integrating the Lob API into your AI agent's workflow.
It also verifies US and international addresses and tracks all mailed pieces.
What AI agents can do with Lob Automation
Autocomplete address
Suggests full address completions based on partial input data.
Create check
Mails a physical check to the recipient with specified payment details.
Create letter
Sends a full-sized physical letter, supporting custom inserts and certified mail options.
Confirms if a US or international address is valid for mailing, providing standardized data.
Creates and sends letters, supporting both PDF and HTML content formats. It also handles certified mail requirements.
Sends physical postcards using custom designs for both the front and the back of the card.
Generates and mails a personalized check, including payee details and memo notes.
Retrieves the current delivery status and tracking information for any sent mail item.
Ask an AI about this
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What AI agents can do with Lob MCP Server: 9 Tools for Direct Mail Operations
These nine tools let your agent handle the entire lifecycle of physical mail, from address validation (US/Intl) to creating letters, checks, and postcards.
Make your AI actually useful.
Add this MCP to Claude, Cursor, or Windsurf and your AI stops guessing. It gets real tools to look things up, take action, and handle the stuff you keep doing by hand.
Start using Lob on VinkiusAutocomplete Address
Suggests full address completions based on partial input data.
Create Check
Mails a physical check to the recipient with specified payment details.
Create Letter
Sends a full-sized physical letter, supporting custom inserts and certified mail...
Create Postcard
Mails a physical postcard, allowing content for both the front and back sides using...
Get Mail Tracking
Checks the current delivery status and location of a specific sent mail piece ID.
List Letters
Retrieves a list of all letters that have been successfully created or mailed through the server.
List Postcards
Gets a record listing of all postcards sent out via the system.
Verify Intl Address
Checks and standardizes addresses that are not in the United States for reliable...
Verify Us Address
Validates a US address, confirming deliverability and providing standardized...
Security and governance baked right in.
Pick your AI client below to get set up. Just create a Vinkius account, subscribe, and you're instantly up and running. We handle the entire backend infrastructure, delivering out-of-the-box support for HTTPS Streamable, SSE, and OAuth2—zero messy routing required.
Claude AI
Open Claude Settings
Go to claude.ai, click your profile icon, then navigate to Customize → Connectors.
Add Custom Connector
Click the "+" button and select Add custom connector. Paste your Vinkius endpoint URL:
https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp
Replace [YOUR_TOKEN_HERE] with your token
from cloud.vinkius.com. For OAuth-protected servers, expand
Advanced settings to add credentials.
Start a conversation
Open a new chat. The Lob integration is available immediately — no restart needed.
Choose How to Get Started
Build a custom MCP for your own tools, or connect a ready-made integration from our catalog.
Build Your Own
Turn any API into an MCP. Import a spec, define Agent Skills, or deploy with MCPFusion.
- Import from OpenAPI, Swagger, or YAML specs
- Create Agent Skills with progressive disclosure
- Deploy to edge with MCPFusion framework
- Built in DLP, auth, and compliance on every call
- Real time usage dashboard and cost metering
- Publish to catalog or keep private
Make Your AI Do More
Start with Lob, then connect any of our 5,100+ other servers whenever your AI needs more. One click, no limits.
- Use this MCP plus 5,100+ others, all in one place
- Add new capabilities to your AI anytime you want
- Every connection is secured and compliant automatically
- Track usage and costs across all your servers
- Works with Claude, ChatGPT, Cursor, and more
- New servers added to the catalog every week
Independent Platform Disclaimer: Vinkius is an independent platform and is not affiliated with, endorsed by, sponsored by, verified by, or otherwise authorized by Lob. All third-party trademarks, logos, and brand names are the property of their respective owners. Their use on this website is strictly for informational purposes to identify service compatibility and interoperability.
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Built on the Model Context Protocol (MCP) for Claude, ChatGPT, Cursor, and more
The Model Context Protocol standardizes how applications expose capabilities to LLMs. Instead of operating in isolation, your AI gains direct access to external platforms, live data, and real-world actions through secure, standardized connections.
This connection provides 9 powerful capabilities that interface natively with Claude, ChatGPT, Cursor, and other compatible AI platforms. No middleware. No custom integration required.
Physical mail shouldn't require a separate logistics team., Solved with Vinkius AI Gateway
Today, if you need to send out a batch of letters or postcards, the process breaks down. You copy-paste addresses into an Excel sheet. Then, you run them through USPS tools or dedicated mailing software just to verify formatting and deliverability. If the data is messy—a missing ZIP code, wrong state abbreviation—the whole campaign stalls until someone manually fixes it.
With this MCP server, your agent handles the entire validation layer first. You provide the raw list of addresses; the agent calls `verify_us_address` or `verify_intl_address`, cleans it up, and then uses that clean data directly to execute `create_letter`. The whole thing happens in one conversation thread.
Lob MCP Server: Automate physical mail with confidence.
The old way meant separate API calls for validation, then a second batch job to send the items, and finally logging into a third dashboard just to check the status. It was slow, brittle, and required three different systems talking to each other.
Now, you ask your agent to 'Send welcome mail to this list.' The agent runs `verify_us_address`, uses that result for `create_postcard`, and immediately reports back with a tracking ID from the action. It’s one single, reliable workflow.
What your AI can actually do with this
You're gonna manage your direct mail programs through natural conversation, sending everything from simple postcards to complex physical checks using your AI agent’s workflow.
To get started, you first need reliable address data. You can use autocomplete_address to suggest full completions for an address when you only have partial information. If you're dealing with domestic mail, run verify_us_address. This tool validates a US address, confirming if it actually gets delivered and giving you standardized formatting that the postal service requires.
If your mailing list isn’t in the United States, don't sweat it; use verify_intl_address. It checks international addresses and standardizes them for reliable mailing anywhere in the world. You always want to verify addresses first before you send a thing out.
When it comes time to mail something physical, you've got options. You can generate full-sized letters with create_letter. This tool supports both PDF and HTML content formats and handles specialized services like certified mail requirements for extra proof of delivery. For postcard campaigns, use create_postcard; this lets you design custom content for both the front side and the back side using either HTML or PDF files.
If you need to issue a payment that needs to be mailed out, run create_check. This generates a personalized physical check, allowing you to specify payee details and memo notes right in the tool call.
After you hit send, you'll want to track it down. You can use get_mail_tracking to instantly check the current delivery status and exact location for any specific sent mail piece ID. For keeping tabs on what’s been executed, you can run list_letters to retrieve a full list of every letter successfully created or mailed through the server.
Similarly, if you need a history of your postcard sends, call list_postcards to get that record.
Every piece of mail—the letters, the postcards, and the checks—is logged here, making it simple to audit your direct marketing efforts right from your agent's chat window.
019dd119-da99-72e0-8645-4786beeb2cb9 
Here's how it actually works
The bottom line is that your agent handles the entire flow—from validating input data to confirming physical delivery status—without you leaving your chat window.
You connect your Lob API Key to the server. This key authorizes the agent to send physical mail.
Your AI client calls a specific tool (e.g., create_postcard) and passes all required data, like recipient addresses or content files.
The server executes the action via Lob's API and returns structured results: confirmation IDs, tracking numbers, status reports, or newly created mail pieces.
Who is this actually for?
This server is for Ops Engineers, Marketing Directors, and Financial Analysts who are tired of manual mail runs. If your job requires sending high volumes of personalized physical materials (checks, letters, postcards) based on data records, this saves hours of repetitive API calls and spreadsheet cross-referencing.
Runs multi-stage direct mail campaigns. They use create_postcard or create_letter tools after running verify_us_address on a mailing list.
Automates billing cycles by using create_check to mail payment notices and confirmation statements, tracking them with list_letters.
Sends personalized welcome packages or follow-up letters. They use address verification tools (verify_us_address) first, then call create_letter to ensure the mailing is correct before sending it.
What Changes When You Connect
Automate multi-step campaigns: Instead of manually checking addresses, you run verify_us_address first. Then, your agent automatically proceeds to create_postcard, guaranteeing the recipient data is clean before mailing begins.
Full visibility on mail status: Don't just assume it was sent. Use get_mail_tracking anytime to check the real-time location of a specific piece, whether it’s in transit or delivered.
Handle complex finance mailings: Forget sending checks via simple email attachments. The create_check tool physically mails professional checks with designated amounts and memos, complete with tracking IDs.
Streamline content creation: You can't just send a basic text file. Use create_letter to manage full PDF/HTML documents and even include certified mail details in one request.
Manage your mailing history: Need an audit trail? Call list_letters or list_postcards. These tools give you immediate, structured access to every piece sent this month.
See it in action
Onboarding a new client
A Customer Success Manager needs to send a welcome package. The agent first calls verify_us_address on the client's address data. If successful, it runs create_letter with a custom PDF insert and then records the transaction using list_letters for later auditing.
Monthly billing cycle closeout
The Finance Analyst needs to send statements and payments. The agent uses create_check for payment notices, and then calls list_postcards to confirm that the accompanying thank-you postcards were also successfully mailed.
International partnership outreach
A Marketing team is reaching out globally. They use verify_intl_address first to validate foreign recipient data, then they pass the clean address into create_postcard to ensure the physical marketing materials don't fail at customs.
Inventory audit and tracking
Operations needs confirmation on old mail batches. Instead of checking paper logs, the agent uses a batch ID to call get_mail_tracking, getting an immediate status report for all items in that run.
The honest tradeoffs
Trying to email physical checks
The user tries to send financial confirmations by just generating a PDF of the check details and attaching it. This fails because the recipient needs an actual, mailed item with tracking.
You must use the create_check tool. It handles the entire printing, mailing, and tracking process for physical checks.
Ignoring international validation
The user inputs an address from Europe directly into a standard letter sending function, which often assumes US formatting, resulting in immediate mail failure.
Always run the address through verify_intl_address first. This validates and formats foreign addresses correctly before attempting to send anything.
Sending multiple items manually
The user has three distinct actions—checking a box, sending a letter, and tracking one piece—and calls them as separate commands without linking the data.
First, verify the address using verify_us_address. Then, chain the action: pass that verified address to both create_letter (to send) and then use the resulting ID in get_mail_tracking for confirmation.
When It Fits, When It Doesn't
Use this server if your primary pain point is converting digital data into reliable, trackable physical mail. You need a system that handles addresses from multiple regions—US via verify_us_address, global via verify_intl_address—and can execute different mail types (letters, postcards, checks) in one automated flow.
Don't use it if you just need to send an email or manage internal documents; those tools are better suited for digital messaging. If all you need is a simple address suggestion without sending anything, autocomplete_address helps, but you’ll still need the other tools to execute the final mailing action.
It's ideal for structured workflows: data comes in -> validation runs -> physical object created/sent -> status recorded.
Questions you might have
How do I check if an address is valid using verify_us_address? +
The verify_us_address tool checks and standardizes US addresses. It returns structured data confirming deliverability, which you can then pass to any sending tool like create_letter.
Can I send a letter with custom inserts using create_letter? +
Yes. The create_letter tool supports complex mailings and allows you to specify multiple content parts, including dedicated fields for certified mail and custom inserts.
What is the difference between list_letters and get_mail_tracking? +
list_letters gives you a historical summary of all letters sent (an inventory view). get_mail_tracking requires a specific ID to check the real-time location of one piece.
Do I need to use verify_intl_address if my recipient is in Canada? +
You should. The verify_intl_address tool handles non-US postal standards and formats, ensuring the mail piece gets routed correctly globally.
Can I send a postcard using HTML or PDF content? (create_postcard) +
Yes. The create_postcard tool supports detailed front and back designs for postcards, accepting either full HTML markup or dedicated PDF files for the content.
What do I need to set up before calling `list_letters`? +
You must provide an active Lob API Key. Make sure this key is loaded into your client environment or passed directly to the server connection. This authenticates your account and lets your AI agent pull your historical mailing records.
How does `autocomplete_address` help with data quality? +
It suggests validated address completions as you input them. You get instant suggestions for street names, ZIP codes, and unit numbers. This prevents typos and ensures the format is correct before you ever try to send or verify a mailing piece.
What happens if I use `create_check` with invalid payment details? +
The service validates all required fields (like amount, recipient, and memo) before processing. If data is incorrect or missing, the API returns a specific error code and message telling you exactly what needs fixing.
Can I send letters and postcards through the AI agent? +
Yes. Create and send letters with PDF/HTML content and postcards with custom designs. Track delivery through the postal system.
Does Lob use Basic Auth? +
Yes. Lob uses HTTP Basic Auth with the API Key as username (no password) against api.lob.com/v1.
Can I verify US addresses? +
Yes. Verify and standardize US addresses with CASS certification. Returns deliverability status, corrected addresses, and coordinates.
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