Send a letter from Email.
Email paperplane a recipient and a letter — in plain language or a TO: block — and reply to the quote it sends back to mail a real USPS letter.
Free to preview — see the exact PDF before you pay. Sending starts at $1.99, no account required.
Not on Email? Any surface works.
The same three calls from the CLI, any MCP client or plain REST. Sandbox is free and mails nothing.
{
"mcpServers": {
"mail": { "url": "https://sendpaperplane.com/api/mcp" }
}
}Common questions
How do I send a letter by email?
Email paperplane’s inbound address with the recipient and letter text — write it like a normal email, or use a "TO:" block (name, address, then the letter) for instant, no-model handling — then reply to the quote it sends back to confirm and mail it.
What if I don’t use a TO: block?
Write the email in your own words. A Claude Haiku layer reads it, asks a follow-up if the recipient or wording is missing or ambiguous, and quotes a real price once it has both. Nothing is mailed until you reply to confirm that specific quote.
Can I send a postcard by email?
Not yet — email-to-send currently creates letters only. Postcards (4x6/6x9/6x11, from $1.99) are live via the web composer and the REST API’s format field.
How much does it cost?
Letters start at $1.99 for First-Class; Certified Mail starts at $12.99. Every quote shows the exact total before you confirm anything.