> ## Documentation Index
> Fetch the complete documentation index at: https://paperplane-justin-winter-s-projects.vercel.app/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Send by email

> Email paperplane a recipient and a letter, in your own words, and get a quote you confirm by replying.

## Email → letter

Send an email to paperplane's inbound address and it turns the thread into a letter order. Two ways to give it the recipient and the letter:

**Just write it like a normal email**, in your own words:

```text theme={null}
Subject: mail a letter for me?

Hey, can you mail this to my aunt? Her name is Ada Lovelace and her
address is 1 Analysis Way, San Francisco, CA 94107. Just let her know
I signed the lease renewal and send my love.
```

paperplane replies asking whatever it's missing — an address, the actual wording — quotes a real price, and mails nothing until you reply to confirm that specific quote.

**Or use the `TO:`/`FROM:` block convention** — the fast path, priced instantly with no model call at all:

```text theme={null}
TO: Ada Lovelace
1 Analysis Way
San Francisco, CA 94107

FROM (your return address):
Alex Rivera
421 8th Ave
New York, NY 10199

SEND EXACTLY:
Please find enclosed the signed lease renewal for the coming year.
Sincerely, Alex Rivera
```

The `FROM:` block is optional but recommended — USPS requires a return address on every physical piece, and when it's present it becomes the order's actual return address instead of paperplane's placeholder one. `SEND EXACTLY:` marks the letter text as final, to mail word for word; use `DRAFT FOR ME:` instead with a description of what you want said, and the natural-language layer (step 3 below) drafts it for you — the deterministic `TO:`-block parser has no drafting capability of its own, so a `DRAFT FOR ME:` email always falls through to that layer, even with a well-formed `TO:` block.

The `TO:`/`FROM:` blocks and the `SEND EXACTLY:`/`DRAFT FOR ME:` labels are all stripped before mailing, so the letter reads cleanly.

## What happens

1. We receive the email and verify it (Svix-signed webhook).
2. We try the deterministic `TO:`-block parser first — it's free, instant, and unambiguous, so a well-formed email never invokes a model at all for pricing. If it finds a valid `TO:` block, a real address, and usable letter text (a `SEND EXACTLY:` section, or the whole remainder when neither label is used), it prices the letter and replies with a quote — nothing is mailed yet. A `DRAFT FOR ME:` section, or no letter text at all, falls through to step 3 instead.
3. If the body doesn't match that shape (or used `DRAFT FOR ME:`), an AI read of the email extracts a recipient and drafts or cleans up the letter content from the natural prose or description, asking a clarifying follow-up by replying to the thread if anything is missing or ambiguous. Once it has both, it gets a real price and replies with a quote — nothing is mailed yet.
4. Only an explicit confirming reply to that specific quote (in a later message) completes the order and mails it; a model output is never enough on its own, the same safety boundary [send by text](/docs/guides/imessage-to-send) uses. We reply to that confirming message with the tracking link.

A well-formed `TO:` block no longer skips the quote — it used to create the order immediately on the first message; it now gets the exact same "here's the price, reply yes to send it" step every other path gets, so nothing is printed or charged off a single email.

Because an email reply carries the whole quoted thread beneath your new text, paperplane looks only at what you actually wrote — above the quoted `>` lines, the "On ... wrote:" header, or an Outlook-style separator — when deciding whether a reply is a confirmation.

## Why the `TO:` block is tried first here, unlike text

Send-by-text tries its conversational layer first and only falls back to strict parsing if the model is unavailable, because a text sender is almost always a person free-texting. Email is different: anyone integrating with the documented `TO:` convention — a script, an automation, a person who read this page — gets instant, free, zero-ambiguity handling every time, and only a human writing in ordinary prose that doesn't match it pays for a model call at all.

## Notes

* The recipient must be a real USPS-verifiable address, same as every other surface.
* If neither the `TO:` block nor the natural-language layer can find enough to work with (and the natural-language layer isn't configured, or is unavailable when it's needed), you'll be asked to add a recipient rather than have one guessed.
* A confirming reply only ever completes the specific quote it was sent for — the recipient, letter content, and price are bound to a single-use token, the same mechanism every other surface uses.
* Test mode: use sandbox-mode orders to test the full flow for free before sending real mail.