Send mail from agents & apps

paperplane is agent-native: the MCP endpoint and REST API are the product, and the website is one more client of them. No account, no API key, no monthly fee — every order carries its own payment.

Use paperplane with your AI agent

Services

4 flagship formats shown; full price list

Plans

Resources

Agent card preview

{
  "name": "paperplane",
  "interfaces": {
    "mcp": { "transport": "streamable-http", "url": "https://sendpaperplane.com/api/mcp" },
    "rest": { "openapi": "https://sendpaperplane.com/v1/openapi.json" }
  },
  "pricing": {
    "model": "per-transaction",
    "currency": "USD",
    "items": [
      { "sku": "first_class", "price": 1.99, "unit": "letter (1 page B&W)" },
      { "sku": "certified", "price": 12.99, "unit": "letter" }
    ]
  },
  "authentication": { "required": false, "scheme": "bearer" }
}

Supported payment methods

How agents pay

1. 01

   Get a quote

   POST /v1/quotes (or the quote_letter MCP tool) prices any letter, free. Returns a confirmation_token bound to the exact recipient, content, class, and price.

2. 02

   Confirm and pay

   POST /v1/orders with that token returns a Stripe payment link for the human to approve (or, for an agent with its own wallet, settles USDC over x402 once that lane is live — see payment methods above). A send is never the first call.

3. 03

   Track the letter

   GET /v1/orders/:id (or get_letter_status) reports the lifecycle from screening to delivered.

npx paperplane send letter.pdf --to "Maria Alvarez, 1 Main St, Richmond VA 23220" --sandbox

Sandbox: pass sandbox: true to run the entire flow — rendering, screening, simulated fulfillment with tracking — instantly and free. An agent's first call can succeed before any human has signed up for anything.

The benchmark, replayed

Claims about being agent-ready are cheap; transcripts aren't. This is the real captured sandbox run — quote → send → track in 3 calls, zero schema retries — including the part where a replayed request and a reused confirmation token both fail to double-send. Full write-up: agent benchmark.

POST /v1/quotes
{
  "mail_class": "certified",
  "page_count": 1,
  "to": {
    "name": "Property LLC",
    "line1": "1 Main St",
    "city": "Richmond",
    "state": "VA",
    "zip": "23220"
  },
  "text": "Formal demand for return of my security deposit within 14 days of this notice."
}

{
  "status": "ok",
  "total_cents": 1299,
  "total": "$12.99",
  "breakdown": [
    {
      "id": "certified_mail_letter_1_page",
      "label": "Certified Mail letter, 1 page",
      "amount_cents": 1299
    }
  ],
  "confirmation_token": "ppq_eyJ2IjoxLCJqdGkiOiJhNDBlZjFiMzFhZDMxYjMx…",
  "expires_in_minutes": 30,
  "next": [
    "POST /v1/orders with this confirmation_token and the same recipient, content, and options."
  ]
}

POST /v1/orders
Idempotency-Key: bench-2026-08-25-a
{
  "mail_class": "certified",
  "sandbox": true,
  "confirmation_token": "ppq_eyJ2IjoxLCJqdGkiOiJhNDBlZjFiMzFhZDMxYjMx…",
  "to": {
    "name": "Property LLC",
    "line1": "1 Main St",
    "city": "Richmond",
    "state": "VA",
    "zip": "23220"
  },
  "from": {
    "name": "Alex Rivera",
    "line1": "12 Grove Ave",
    "city": "Richmond",
    "state": "VA",
    "zip": "23221"
  },
  "text": "Formal demand for return of my security deposit within 14 days of this notice."
}

{
  "status": "ok",
  "order": {
    "id": "ord_test_f5ca66ace638fdc1",
    "status": "submitted",
    "sandbox": true,
    "price_cents": 1299,
    "tracking_number": "9400MOCK00000001"
  },
  "corrected_to": {
    "name": "Property LLC",
    "line1": "1 MAIN ST",
    "city": "RICHMOND",
    "state": "VA",
    "zip": "23220"
  },
  "capability": {
    "cancel_token": "…",
    "review_token": "…"
  }
}

GET /v1/orders/ord_test_f5ca66ace638fdc1

{
  "status": "ok",
  "order": {
    "status": "submitted",
    "tracking_number": "9400MOCK00000001",
    "…": "…"
  }
}

POST /v1/orders
Idempotency-Key: bench-2026-08-25-a

{
  "status": "ok",
  "replayed": true,
  "order": {
    "id": "ord_test_f5ca66ace638fdc1",
    "…": "…"
  }
}

POST /v1/orders

POST /v1/orders

Every failure that transcript beat could have ended on, rendered the same way: the full error contract, visually.

MCP: Claude, agents, any MCP client

Pick your client for the exact config. The field name differs more than you would expect.

claude mcp add --transport http paperplane https://sendpaperplane.com/api/mcp

Using the paperplane tools, quote a 1-page certified letter to Property LLC, 1 Main St, Richmond VA 23220, then send it in sandbox mode.

Three tools, deliberately only three:

• quote_letter — price any letter, free, returns the all-in total.
• send_letter — text or pdf_url + addresses → returns a Stripe payment link for the human to approve. After payment, screening, printing, and mailing are automatic.
• get_letter_status — lifecycle from screening to delivered.

Look up an order's events

Every order's real event log — screening, submission, provider webhooks — not just its current status. Paste any real order id (yours, or the one the benchmark above just replayed) to see it.

Developer console

Sign in to see your letters in one place — live status, tracking, and receipts — even though sending stays keyless.

Sign in

REST

curl -X POST https://sendpaperplane.com/v1/orders \
  -H 'Content-Type: application/json' \
  -d '{
    "mail_class": "certified",
    "sandbox": true,
    "text": "Formal demand for return of my security deposit...",
    "to":   { "name": "Property LLC", "line1": "1 Main St",
              "city": "Richmond", "state": "VA", "zip": "23220" },
    "from": { "name": "Alex Rivera", "line1": "12 Grove Ave",
              "city": "Richmond", "state": "VA", "zip": "23221" },
    "email": "alex@example.com"
  }'

• POST /v1/quotes — price without creating anything.
• POST /v1/uploads — signed URL for uploading a PDF straight to storage; PUT the file to it, then pass the returned upload_key instead of pdf_base64. Avoids base64 inflation and the request body limit.
• POST /v1/orders — create; returns payment_url (live) or a completed sandbox order.
• GET /v1/orders/:id — status. DELETE cancels any pre-print order and releases payment.

Try it — a real sandbox round trip

Not a mock. Edit the request below and this calls this deployment's own POST /v1/quotes, then POST /v1/orders with sandbox: true — real screening runs, a real sandbox order is created, nothing is printed, mailed, or charged.

Error contract

Every error is structured for agents: { status, code, reason, next: ["what to do"] }. Address problems return the USPS-corrected candidate. Nothing requires reading HTML or guessing.

Content rules

Every letter is screened before printing (policy). Lawful demand letters and firm legal language are explicitly allowed; threats, fraud, and impersonation are refused and the payment released.

npx paperplane send letter.pdf \
  --to "Maria Alvarez, 1 Main St, Richmond VA 23220" \
  --from "Alex Rivera, 12 Grove Ave, Richmond VA 23221" \
  --sandbox