US Business Letter API

Create professional US business letters from structured JSON data. Full sender and recipient address blocks, configurable salutation and closing, and an optional notary page for legal documents.

Example output

Download example PDF →

Quick start

curl -X POST https://api.lobsterpdf.com/render/us_letter \
  -H "Content-Type: application/json" \
  -d '{"sender":{"name":"Jane Smith"},"recipient":{"name":"Acme Corp"},"signer":"Jane Smith","body":"Please find our proposal enclosed."}'

{"url": "https://api.lobsterpdf.com/pdf/a1b2c3d4e5f6"}

Fields

Required: sender, recipient, signer, body

Optional: date, subject, salutation, closing, attachments, notary_page, paper, margin, signature, signature_format

Full schema reference & field details →

Example JSON

{
  "sender": {
    "name": "Jane Smith"
  },
  "recipient": {
    "name": "Acme Corp"
  },
  "signer": "Jane Smith",
  "body": "Please find our proposal enclosed."
}

Why US Business Letter API?

• Standards-compliant — not “looks about right”, actually follows the spec
• JSON in, PDF out — no HTML, no LaTeX, no template files to manage
• Built for automation — structured errors, JSON schemas, MCP support
• Free during beta — no credit card, no rate limits

Use with AI agents

LobsterPDF is purpose-built for LLM agents. Use the MCP endpoint for native tool discovery, or call the REST API directly. Token-efficient schemas mean lower cost per call.

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