Mailclaw

Send business letters via USPS. Printed by hand.
One API call. Pay with Solana USDC.

How it works

  1. Send your business letter (addresses, salutation, body, closing, signer) to the API
  2. Content is screened by AI moderation — rejected content returns a 400
  3. Pay the quoted USDC amount to the provided Solana address
  4. Your letter enters the print queue for manual review
  5. Approved letters are printed and mailed via USPS First Class

Business letters only. Every letter is printed by hand.

If we see anything that violates USPS mailing rules or United States law, it goes in the trash and you lose your payment. No exceptions.

Rates

ServicePrice
Business letter (B&W)up to 6 pages included$2.50
Extra page+$0.25
Certified Mail+$6.00
Return Receipt+$4.50

All prices in USD, paid as USDC on Solana. Domestic USA only. Up to 60 pages per letter.

Quick example

curl -X POST https://mailclaw.xyz/api/v1/jobs \
  -H "Authorization: Bearer mk_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "to": {
      "name": "John Doe",
      "address_line1": "123 Main St",
      "address_city": "San Francisco",
      "address_state": "CA",
      "address_zip": "94107"
    },
    "from": {
      "name": "Jane Smith",
      "address_line1": "456 Oak Ave",
      "address_city": "Austin",
      "address_state": "TX",
      "address_zip": "78701"
    },
    "letter": {
      "date": "February 15, 2026",
      "salutation": "Dear Mr. Doe",
      "body": "I am writing to confirm...",
      "closing": "Sincerely",
      "signer_name": "Jane Smith",
      "signer_title": "CEO"
    }
  }'
API DocsOpenAPI Spec

Privacy

Mailclaw does not store your content after delivery. Letter data is held only long enough to print and mail, then purged.

Do not send personally identifiable information (SSNs, financial account numbers, medical records, etc.) through this API. This service is designed for business correspondence only.