:mailbox_with_mail: solmail-mcp
Send real physical mail using Solana cryptocurrency from your AI agent. A Model Context Protocol server that enables Claude and other AI agents to send physical letters and postcards to real addresses worldwide, paid with SOL. Built for the Colosseum Agent Hackathon (#47).
Install
npx solmail-mcp@latest
Add to your MCP config:
{
"mcpServers": {
"solmail": {
"command": "npx",
"args": ["-y", "solmail-mcp"],
"env": {
"SOLANA_NETWORK": "devnet",
"SOLANA_PRIVATE_KEY": "your_base58_private_key"
}
}
}
}
Features
- Physical Mail -- Letters printed and mailed to 200+ countries via Lob.com
- Solana Payments -- Pay with SOL on devnet (testing) or mainnet (production)
- Non-Custodial -- Direct wallet control, no intermediaries
- AI-Native -- Built specifically for MCP agent integration
- Demo Mode -- Test with devnet SOL and Lob test API at zero cost
Tools (4)
| Tool | Description |
|---|---|
get_mail_quote | Get price quote for sending mail (country, color options) |
send_mail | Send a physical letter with Solana payment |
get_wallet_balance | Check agent wallet SOL balance |
get_wallet_address | Get wallet address for funding |
Usage Example
You: Send a thank you note to John Doe at 123 Main St, San Francisco, CA 94102
Claude: [calls get_mail_quote] Cost: $1.50 (~0.015 SOL) for domestic US mail
[calls send_mail] Letter sent!
Letter ID: ltr_abc123
Tracking: 9400000000000000000000
Payment: 0.015 SOL (tx: 5j7s...)
Delivery: 3-5 business days
How It Works
Agent composes letter --> MCP validates address --> Solana tx signed
--> Payment sent to merchant --> SolMail verifies on-chain
--> Lob.com prints letter --> USPS delivers --> Tracking returned
Pricing
| Type | Price | SOL (at $100/SOL) |
|---|---|---|
| US Domestic | $1.50 | ~0.015 SOL |
| International | $2.50 | ~0.025 SOL |
| Color printing | +$0.50 | +0.005 SOL |
| Solana tx fee | ~$0.00025 | ~0.0000025 SOL |
Configuration
| Variable | Required | Description |
|---|---|---|
SOLANA_PRIVATE_KEY | Yes | Agent wallet private key (base58) |
SOLANA_NETWORK | No | devnet (default) or mainnet-beta |
SOLMAIL_API_URL | No | API endpoint (default: https://solmail.online/api) |
MERCHANT_WALLET | No | Custom payment destination |
Important: Create a dedicated wallet with limited funds for AI agents. Never use your primary wallet.
Development
npm install && npm run build
npm run dev # Watch mode
npm start # Production
Related Projects
- solana-mcp-server-app -- Solana wallet + DeFi MCP
- coldstar-colosseum -- Air-gapped Solana vault
- ordinals-mcp -- Bitcoin Ordinals MCP server
- cpanel-mcp -- cPanel hosting MCP server
Contributing
- Fork the repository
- Create your feature branch (
git checkout -b feature/my-feature) - Commit your changes
- Open a Pull Request
Links
License
MIT -- Purple Squirrel Media