What types of physical mail can I send with Lob?

Lob supports three main mail types: Letters (formal correspondence, invoices, notifications with customizable color, double-sided printing), Postcards (marketing campaigns, invitations, reminders in 4x6, 6x9, or 6x11 sizes), and Checks (vendor payments, payroll, refunds, rebates with customizable memo lines and company logos). All mail is printed and mailed within 24 hours via USPS.

How does Lob address verification work?

Lob's address verification validates and standardizes addresses using USPS data. It corrects formatting, adds missing ZIP+4 codes, fixes typos, and confirms deliverability. The service returns a deliverability status: 'deliverable' (valid and deliverable), 'undeliverable' (cannot be delivered), or 'deliverable_unnecessary' (valid but additional info not needed). This reduces returned mail by up to 5% and ensures your mailings reach the correct destination.

Can I use HTML templates for personalized mailings?

Yes! Lob supports HTML templates with merge variables using the Handlebars templating engine. Create a template with placeholders like {{name}}, {{order_number}}, {{delivery_date}}, then pass actual values when creating letters or postcards. This enables personalized, scalable direct mail campaigns. Templates are reusable and can be referenced by ID when creating mailings. You can also embed CSS styling for professional-looking mail designs.

How long does it take for mail to be delivered?

Lob prints and mails all items within 24 hours of creation. Delivery time depends on the mail type selected: USPS First Class Mail typically delivers in 2-5 business days, while USPS Standard Mail takes 3-7 business days. You receive a tracking number for each piece of mail to monitor delivery status. Lob also provides expected delivery dates in API responses for planning purposes.

Lob MCP Server for LlamaIndex 21 tools — connect in under 2 minutes

Name: Lob
Availability: InStock
Author: Vinkius

docs.llamaindex.ai/en/stable/module_guides/tools/mcp

Built by Vinkius GDPR 21 Tools Framework

LlamaIndex specializes in data-aware AI agents that connect LLMs to structured and unstructured sources. Add Lob as an MCP tool provider through the Vinkius and your agents can query, analyze, and act on live data alongside your existing indexes.

Get MCP Server for AI Agents

ASK AI ABOUT THIS MCP SERVER

Open in ChatGPT Open in Claude Open in Perplexity

Vinkius supports streamable HTTP and SSE.

python

import asyncio
from llama_index.tools.mcp import BasicMCPClient, McpToolSpec
from llama_index.core.agent.workflow import FunctionAgent
from llama_index.llms.openai import OpenAI

async def main():
    # Your Vinkius token — get it at cloud.vinkius.com
    mcp_client = BasicMCPClient("https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp")
    mcp_tool_spec = McpToolSpec(client=mcp_client)
    tools = await mcp_tool_spec.to_tool_list_async()

    agent = FunctionAgent(
        tools=tools,
        llm=OpenAI(model="gpt-4o"),
        system_prompt=(
            "You are an assistant with access to Lob. "
            "You have 21 tools available."
        ),
    )

    response = await agent.run(
        "What tools are available in Lob?"
    )
    print(response)

asyncio.run(main())

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About Lob MCP Server

Lob MCP Server enables AI agents to send physical mail directly from your applications. Create and mail letters, postcards, and checks programmatically through Lob's print and mail API. Verify US and international addresses, autocomplete partial addresses, and manage your address book. Build reusable HTML templates for personalized mailings. Perfect for automating vendor payments, customer communications, marketing campaigns, payroll checks, and direct mail operations. All mail is printed, processed, and delivered within 24 hours via USPS integration.

LlamaIndex agents combine Lob tool responses with indexed documents for comprehensive, grounded answers. Connect 21 tools through the Vinkius and query live data alongside vector stores and SQL databases in a single turn — ideal for hybrid search, data enrichment, and analytical workflows.

The Lob MCP Server exposes 21 tools through the Vinkius. Connect it to LlamaIndex 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 Lob to LlamaIndex via MCP

Follow these steps to integrate the Lob MCP Server with LlamaIndex.

Install dependencies

Run pip install llama-index-tools-mcp llama-index-llms-openai

Replace the token

Replace [YOUR_TOKEN_HERE] with your Vinkius token

Run the agent

Save to agent.py and run: python agent.py

Explore tools

The agent discovers 21 tools from Lob

Why Use LlamaIndex with the Lob MCP Server

LlamaIndex provides unique advantages when paired with Lob through the Model Context Protocol.

Data-first architecture: LlamaIndex agents combine Lob tool responses with indexed documents for comprehensive, grounded answers

Query pipeline framework lets you chain Lob tool calls with transformations, filters, and re-rankers in a typed pipeline

Multi-source reasoning: agents can query Lob, a vector store, and a SQL database in a single turn and synthesize results

Observability integrations show exactly what Lob tools were called, what data was returned, and how it influenced the final answer

Lob + LlamaIndex Use Cases

Practical scenarios where LlamaIndex combined with the Lob MCP Server delivers measurable value.

Hybrid search: combine Lob real-time data with embedded document indexes for answers that are both current and comprehensive

Data enrichment: query Lob to augment indexed data with live information before generating user-facing responses

Knowledge base agents: build agents that maintain and update knowledge bases by periodically querying Lob for fresh data

Analytical workflows: chain Lob queries with LlamaIndex's data connectors to build multi-source analytical reports

Lob MCP Tools for LlamaIndex (21)

These 21 tools become available when you connect Lob to LlamaIndex via MCP:

autocomplete_us_address

Autocomplete a partial US address

cancel_letter

Only works if status is still "processing". Cancel a letter before it enters production

create_address

Requires name and address_line1. Create a new address in your Lob address book

create_bank_account

Requires description, routing_number, account_number, account_type (company/individual), and signatory. Add a bank account for sending checks

create_check

Requires recipient (to), bank account ID, and amount. Optional: memo, logo, description. Create and mail a physical check through Lob

create_letter

Requires recipient (to), sender (from), and file content. Supports HTML templates with merge variables, color options, and mail type selection. Create and mail a physical letter through Lob

create_postcard

Requires recipient (to) and front design. Optional: back design, message, merge variables. Create and mail a physical postcard through Lob

create_template

Create a reusable HTML template for mailings

delete_address

Delete an address from your Lob address book

get_address

Get details of a specific address

get_check

Get details of a specific check by ID

get_letter

Get details of a specific letter by ID

get_postcard

Get details of a specific postcard by ID

get_template

Get details of a specific template

list_addresses

Use optional limit to control result count. List addresses in your Lob address book

list_bank_accounts

Use optional limit to control result count. List bank accounts in your Lob account

list_checks

Track payments, audit disbursements. List physical checks sent through Lob

list_letters

Each letter includes status, tracking number, and expected delivery date. Use optional limit to control result count. List physical letters sent through Lob. Track mailings, check delivery status, and review letter history

list_postcards

Use optional limit to control result count. List physical postcards sent through Lob

list_templates

List HTML templates for mailings

verify_us_address

Verify and standardize a US address

Example Prompts for Lob in LlamaIndex

Ready-to-use prompts you can give your LlamaIndex agent to start working with Lob immediately.

"Send a letter to John Doe at 123 Main St, New York, NY 10001 with our welcome package HTML template"

"Verify if this address is deliverable: 185 Berry St, San Francisco, CA 94107"

"Send a $500 check to ABC Consulting for consulting services rendered in March"

Troubleshooting Lob MCP Server with LlamaIndex

Common issues when connecting Lob to LlamaIndex through the Vinkius, and how to resolve them.

BasicMCPClient not found

Install: pip install llama-index-tools-mcp

Lob + LlamaIndex FAQ

Common questions about integrating Lob MCP Server with LlamaIndex.

How does LlamaIndex connect to MCP servers?

Use the MCP client adapter to create a connection. LlamaIndex discovers all tools and wraps them as query engine tools compatible with any LlamaIndex agent.