Solmail

io.github.ExpertVagabondPublished by GitHub account ExpertVagabondv1.0.2Updated Oct 24, 2026

Send physical mail with Solana cryptocurrency - AI agents can send real letters worldwide

VerifiedSTDIODesktop onlyFinanceBusiness & Commerce

Overview

AI-generated overview

Lets an assistant quote and send real physical letters and postcards worldwide, paying with Solana cryptocurrency from an agent wallet.

What you can do
Solmail exposes four tools: get_mail_quote for pricing by country and color options, send_mail to dispatch a physical letter paid in SOL, get_wallet_balance to check the agent wallet's SOL balance, and get_wallet_address to obtain a wallet address for funding. Letters are printed and mailed through Lob.com to addresses in 200+ countries, and a tracking number and transaction reference are returned. A devnet demo mode allows testing with test SOL and Lob's test API at no cost.
When to use it
Use it when an assistant should send tangible mail — thank-you notes, notifications, or marketing letters — to a real postal address and pay per item in SOL. It suits agent workflows that already hold a Solana wallet and want physical delivery with tracking, rather than email or digital messaging.
Requirements
Runs locally as an npm package (npx solmail-mcp) over stdio, so Node.js is needed. Requires the SOLANA_PRIVATE_KEY environment variable holding the agent wallet's private key; SOLANA_NETWORK selects devnet (default) or mainnet-beta, and SOLMAIL_API_URL and MERCHANT_WALLET are optional. Network access to the SolMail API and the Solana network is required, and the wallet must be funded with SOL.
Before you install
The server requires SOLANA_PRIVATE_KEY, a wallet private key, so use a dedicated wallet with limited funds and never a primary wallet. On mainnet-beta, send_mail spends real SOL per letter, with prices around $1.50 domestic and $2.50 international plus color and transaction fees. Sending mail submits a payment transaction and shares the recipient's postal address and letter content with the SolMail service and Lob.com for printing and delivery.

Installation

In SourceWeft

  1. Open Solmail in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

:mailbox_with_mail: solmail-mcp

[npm version] [License: MIT] [GitHub stars] [Solana]

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

bash
npx solmail-mcp@latest

Add to your MCP config:

json
{  "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)

ToolDescription
get_mail_quoteGet price quote for sending mail (country, color options)
send_mailSend a physical letter with Solana payment
get_wallet_balanceCheck agent wallet SOL balance
get_wallet_addressGet 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

TypePriceSOL (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

VariableRequiredDescription
SOLANA_PRIVATE_KEYYesAgent wallet private key (base58)
SOLANA_NETWORKNodevnet (default) or mainnet-beta
SOLMAIL_API_URLNoAPI endpoint (default: https://solmail.online/api)
MERCHANT_WALLETNoCustom payment destination

Important: Create a dedicated wallet with limited funds for AI agents. Never use your primary wallet.

Development

bash
npm install && npm run buildnpm run dev    # Watch modenpm start      # Production

Related Projects

Contributing

  1. Fork the repository
  2. Create your feature branch (git checkout -b feature/my-feature)
  3. Commit your changes
  4. Open a Pull Request

Links

License

MIT -- Purple Squirrel Media

Source: README.md at commit 990a8ab

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v1.0.2LatestSep 16, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts