SolMail MCP enables AI agents to send real physical mail worldwide using Solana cryptocurrency.
Send physical mail (send_mail): Compose and send letters/postcards to real addresses in 200+ countries, specifying recipient details, content, color printing, double-sided printing, and mail class (standard/first_class/priority). Returns a letter ID and tracking information on success.
Get price quotes (get_mail_quote): Check the cost of sending mail based on destination country and printing options, returned in both USD and estimated SOL.
Check wallet balance (get_wallet_balance): View the current SOL balance of the configured agent wallet.
Get wallet address (get_wallet_address): Retrieve the public Solana wallet address for funding purposes.
Solana payments: Pay for mail using SOL on devnet (testing) or mainnet-beta (production), operating non-custodially with direct wallet control.
Demo/test mode: Use devnet SOL and Lob's test API at zero real cost for development and testing.
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 "Deploy 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 MCP send 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.
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).
npx solmail-mcp@latestAdd to your MCP config:
{
"mcpServers": {
"solmail": {
"command": "npx",
"args": ["-y", "solmail-mcp"],
"env": {
"SOLANA_NETWORK": "devnet",
"SOLANA_PRIVATE_KEY": "your_base58_private_key"
}
}
}
}Related MCP server: postcardbot-mcp-server
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
Tool | Description |
| Get price quote for sending mail (country, color options) |
| Send a physical letter with Solana payment |
| Check agent wallet SOL balance |
| Get wallet address for funding |
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 daysAgent composes letter --> MCP validates address --> Solana tx signed
--> Payment sent to merchant --> SolMail verifies on-chain
--> Lob.com prints letter --> USPS delivers --> Tracking returnedType | 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 |
Variable | Required | Description |
| Yes | Agent wallet private key (base58) |
| No |
|
| No | API endpoint (default: |
| No | Custom payment destination |
Important: Create a dedicated wallet with limited funds for AI agents. Never use your primary wallet.
npm install && npm run build
npm run dev # Watch mode
npm start # Productionsolana-mcp-server-app -- Solana wallet + DeFi MCP
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Fork the repository
Create your feature branch (git checkout -b feature/my-feature)
Commit your changes
Open a Pull Request
MIT -- Purple Squirrel Media
Get a price quote for sending physical mail. Returns price in USD and estimated SOL amount based on current exchange rates.
Inputs: country, color.
Get the public address of the configured wallet. Useful for receiving funds.
Inputs: no named parameters.
Get the current SOL balance of the configured wallet. Requires wallet configuration.
Inputs: no named parameters.
Send physical mail using Solana cryptocurrency. Composes a letter, creates a Solana payment transaction, and submits to SolMail for printing and mailing. Requires wallet configuration.
Inputs: content (required), recipient (required), mailOptions.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
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Scored across 4 tools
Each tool has a clearly distinct purpose: get_mail_quote for pricing, get_wallet_address for address retrieval, get_wallet_balance for balance checking, and send_mail for the core mailing action. There is no overlap or ambiguity between these functions, making tool selection straightforward for an agent.
All tool names follow a consistent verb_noun pattern using snake_case: get_mail_quote, get_wallet_address, get_wallet_balance, and send_mail. The verbs 'get' and 'send' are appropriately applied, and there are no deviations or mixed conventions, ensuring predictable naming throughout.
With 4 tools, the count is reasonable for the server's purpose of handling physical mail via Solana. It covers essential operations like quoting, wallet management, and sending, though it might be slightly thin if advanced features like tracking or cancellation were expected. Overall, it's well-scoped but could benefit from minor additions.
The tool set covers the core workflow: quoting, wallet setup, and sending mail. However, there are minor gaps, such as missing tools for tracking sent mail, canceling transactions, or managing mail templates, which could limit agent flexibility in more complex scenarios. The basics are well-covered, but the surface is not fully comprehensive.
Let AI agents prepare, review, pay for, and send real letters and postcards.
Write, preview and mail real letters and postcards to US addresses from your AI app.
Send real paper letters from AI chat: print, envelope, postage, delivery. Pay per letter.
The agentic layer of letters. Agents send real printed mail worldwide, German compliance built in.
