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Use paperplane in Lindy

Justin WinterBy · Updated August 26, 2026

Lindy connects to any MCP server, and paperplane is one: in Lindy go to Integrations → + Add → MCP, paste https://sendpaperplane.com/api/mcp as the Server URL, and Connect — no credentials needed. Your agents gain quote_letter, send_letter, and get_letter_status: real USPS mail from $1.99, with a free sandbox mode to test flows before any money moves.

Lindy agents can use tools from any MCP server, and paperplane’s MCP endpoint is public — no API key, no OAuth. That means a Lindy that handles your ops inbox, chases invoices, or runs a compliance workflow can also put real paper in the USPS mail stream. Honest framing up front: this is user-side setup. paperplane has no native listing in Lindy’s integration library yet — you are adding our standard MCP server to your own workspace, the same endpoint every other MCP client uses.

Connect it

  • In Lindy, open Integrations and click + Add, then choose MCP.
  • In the “Connect MCP server” dialog, paste the Server URL: https://sendpaperplane.com/api/mcp and give it a display name like paperplane.
  • Skip the Advanced credentials section — the server supports anonymous access, so there is no bearer token or header to add.
  • Click Connect. The server appears in your list with its tool count (three), and you can choose whether it is available to just you or workspace-wide.
  • In the guardrails settings, consider requiring approval for send_letter while leaving the two read-only tools automatic — see the FAQ below.

What your agent can now do

  • quote_letter — free, read-only. Returns the price (First-Class $1.99, Certified $12.99, Certified + electronic Return Receipt $14.99, Priority $24.99) and, when given the real recipient and letter content, a single-use confirmation_token bound to exactly that letter at exactly that price.
  • send_letter — the write tool. Requires the token, so the recipient, content, and price can’t drift between what was quoted and what gets mailed. Live sends return a Stripe payment link (or draw from a prepaid credit balance); sandbox: true completes instantly and free.
  • get_letter_status — read-only order tracking through screening → printing → mailed → delivered, so an agent can report back or branch on delivery.

Sandbox-first walkthrough

Before wiring paperplane into a real workflow, run one sandbox send in a test conversation with your Lindy:

"Using the paperplane tools: quote a one-page First-Class letter to
Maria Alvarez, 1 Main St, Richmond VA 23220 saying 'This is a test of our
mail integration.' Show me the price, then send it in sandbox mode."

You should see the agent call quote_letter, surface a $1.99 quote with a confirmation_token, then call send_letter with the same letter plus sandbox: true. The response is a completed sandbox order with an id you can feed to get_letter_status. Nothing was printed or charged. When the flow looks right, remove the sandbox instruction; for hands-off live sending, fund a prepaid credit balance and give the agent the credit code.

Where this fits in a Lindy workflow

The natural pattern is mail as the last step of a flow Lindy already runs: an overdue-invoice chaser that escalates from email to a certified demand letter, a compliance Lindy that mails termination or notice letters your ERP generates, an onboarding agent that sends a real welcome note. Because quote_letter is free, agents can price options mid-conversation (“certified or first-class?”) before anyone commits to anything.

Prefer plain HTTP from a Lindy step instead of MCP? The same backend is REST — POST /v1/quotes, POST /v1/orders, GET /v1/orders/:id — documented on the developer docs. And the full mechanics of the quote→send token contract are in how AI agents mail letters via MCP, or live in the no-signup demo.

Related guides

Common questions

Is paperplane a native Lindy integration?

No — paperplane is not in Lindy’s built-in integration library today. You connect it yourself through Lindy’s generic MCP support, which is designed exactly for this. The setup is one URL and takes about a minute.

Can a Lindy agent mail letters completely unattended?

Sandbox letters, yes. Live letters need payment: either a human approves the Stripe payment link the send returns, or you give the agent a prepaid credit code (pp-xxxx-xxxx-xxxx) and sends draw from that balance hands-off. Either way send_letter first requires a confirmation_token from a matching quote — a send is never the first call.

Should tool use be automatic or approval-gated?

Lindy lets you set guardrails per tool. A sensible split: let quote_letter and get_letter_status run automatically (both read-only and free) and require approval for send_letter, the one tool that spends money and mails a physical object.

What does testing cost?

Nothing. quote_letter is always free, and send_letter with sandbox: true exercises the full pipeline — address verification, screening, simulated printing and tracking — without printing, mailing, or charging anything.

Use paperplane in Lindy

First-Class $1.99 · Certified $12.99 · Certified + Return Receipt $14.99

Read the developer docs