Enables AI agents to pay for physical mail services using Solana (SOL) cryptocurrency, providing tools to get quotes, check wallet balances, and manage on-chain transactions.
Facilitates the sending of real physical letters and postcards to addresses worldwide, with fulfillment including delivery via the United States Postal Service (USPS).
Click on "Install Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@SolMail MCPsend a physical letter to John Doe at 123 Main St, SF saying 'Thanks for your help!'"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
SolMail MCP Server
Send real physical mail using Solana cryptocurrency from your AI agent.
SolMail MCP is a Model Context Protocol (MCP) server that enables AI agents like Claude to send physical letters and postcards to real addresses worldwide, paid for with Solana (SOL) cryptocurrency. Perfect for agents that need to interact with the physical world.
Features
π¬ Send Real Mail: Physical letters printed and mailed to any address
π° Crypto Payments: Pay with SOL on Solana (devnet or mainnet)
π Worldwide Delivery: Send to 200+ countries
π€ AI-Native: Built specifically for AI agent integration
β‘ Fast & Cheap: Solana's sub-second finality and ~$0.00025 transaction fees
π Non-Custodial: Direct wallet control, no intermediaries
Use Cases
Autonomous Customer Service: AI agents sending thank-you notes or receipts
AI-Driven Marketing: Personalized postcards generated and sent by AI
Smart Contracts: Trigger physical mail based on on-chain events
AI Personal Assistant: "Claude, send a birthday card to my mom"
Automated Reminders: Physical notifications for important events
Installation
Configuration
Create a .env file based on .env.example:
Getting a Solana Wallet
To use this MCP server, your AI agent needs its own Solana wallet:
Important: For AI agents, create a dedicated wallet and only fund it with the amount needed for mail sending. Never use your primary wallet.
Funding Your Wallet
For Devnet (Testing):
For Mainnet (Production): Transfer SOL to your agent's wallet address. Each letter costs approximately:
Domestic (US): $1.50 = ~0.015 SOL (at $100/SOL)
International: $2.50 = ~0.025 SOL (at $100/SOL)
Plus Solana transaction fee: ~$0.00025
Usage with Claude Desktop
Add to your Claude Desktop MCP settings file:
macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json
Restart Claude Desktop after adding the configuration.
Available Tools
get_mail_quote
Get a price quote for sending mail.
Input:
Output:
send_mail
Send physical mail with Solana payment.
Input:
Output:
get_wallet_balance
Check your agent's wallet balance.
Output:
get_wallet_address
Get your agent's wallet address for funding.
Output:
Example Conversations
With Claude:
How It Works
Agent composes letter content
MCP server validates recipient address
Solana transaction is created and signed by agent's wallet
Payment is sent to SolMail merchant wallet
Transaction signature is submitted to SolMail API
SolMail verifies the on-chain payment
Letter is printed by fulfillment partner (Lob.com)
Letter is mailed via USPS/postal service
Tracking info returned to agent
Architecture
Pricing
US Domestic Letter: $1.50
International Letter: $2.50
Color Printing: +$0.50
Solana Transaction Fee: ~$0.00025
Prices are in USD and automatically converted to SOL at current market rates using CoinGecko API.
Development
Security Considerations
Dedicated Wallet: Create a separate wallet for your AI agent with limited funds
Private Key Security: Store
SOLANA_PRIVATE_KEYsecurely, never commit to gitDevnet Testing: Test thoroughly on devnet before using mainnet
Rate Limiting: Implement spending limits for autonomous agents
Content Review: Consider reviewing mail content before sending (for production)
Limitations
Currently supports plain text letters only (PDF support coming soon)
Requires wallet with SOL balance
Subject to postal delivery times (not instant)
Mail content reviewed by fulfillment partner (Lob.com) for policy compliance
Roadmap
PDF attachment support
Multiple letter templates
Postcard support
Package/merchandise shipping
Return address management
Bulk sending optimization
USDC payment support
Multi-chain support (EVM chains)
Support & Links
Website: https://solmail.online
API Docs: https://solmail.online/docs
Solana Docs: https://docs.solana.com
MCP Docs: https://modelcontextprotocol.io
License
MIT
Credits
Built with:
Model Context Protocol by Anthropic
Solana blockchain
Lob.com print & mail API
Made for the Colosseum Agent Hackathon ποΈ
Bridging AI agents and the physical world, one letter at a time.