> ## Documentation Index
> Fetch the complete documentation index at: https://docs.paperjoy.co/llms.txt
> Use this file to discover all available pages before exploring further.

# Write the card

> How much text fits, how line breaks work, and how to pick the handwriting and signature.

Every Paperjoy postcard is an A6 card (148 × 105 mm) written with a real pen. Your message starts at the top, and the signature sits in the bottom left corner. An 8 mm margin stays empty on every side.

All examples on this page are real previews from the Paperjoy renderer.

## Message

| Rule | Value |
| - | - |
| Length | Up to 300 characters |
| Line breaks | Kept exactly, including blank lines |
| Wrapping | Automatic, between words |
| Characters | Letters, numbers, punctuation, and Polish diacritics (ą, ć, ę, ł, ń, ó, ś, ź, ż) |

### Line breaks

Use `\n` in JSON (or press Enter in the editor) to start a new line. A blank line (`\n\n`) adds space between paragraphs.

```json theme={null}
{
  "content": "Hi Peter!\n\nHappy birthday from all of us.\n\nWarm regards,"
}
```

![A postcard with three short paragraphs separated by blank lines: Hi Peter!, Happy birthday from all of us., Warm regards,](https://mintcdn.com/paperjoy/F1MJj4Vyrx0MCZIR/images/postcards/card-newlines-en.webp?fit=max\&auto=format\&n=F1MJj4Vyrx0MCZIR\&q=85\&s=a8fbb1e8a95f29f32b9f5716fcf8dc7b)

### Make it fit

Paperjoy writes at the largest size that fits. Long messages are written slightly smaller, down to 75% of the normal size. If the text still doesn't fit, Paperjoy rejects the postcard with a `422` error instead of cutting your message:

```json theme={null}
{
  "message": "The content does not fit on the postcard. Shorten it or remove blank lines.",
  "errors": {
    "content": ["The content does not fit on the postcard. Shorten it or remove blank lines."]
  }
}
```

Short words, few blank lines, and a short signature leave the most room. Around 200 characters is a comfortable length for most cards.

> [!TIP]
>
> [Preview the card](https://docs.paperjoy.co/en/postcards/preview.md) before you order. If the text doesn't fit, the preview returns the same `422` error, so you can check dynamic text without spending a credit.

## Handwriting

Choose the style with `font_id`. Both fonts support Polish characters.

> [tab] font-1 · Standard
>
> Clear, rounded, and easy to read. Called **Standardowe** in the editor.
>
> ![A postcard written in font-1, a clear upright handwriting.](https://mintcdn.com/paperjoy/F1MJj4Vyrx0MCZIR/images/postcards/card-font-1-en.webp?fit=max\&auto=format\&n=F1MJj4Vyrx0MCZIR\&q=85\&s=d30ca0c907f880a0e1249fc1e3c514f0)

> [tab] font-2 · Fast
>
> Joined-up cursive that looks written in one go. Called **Szybkie** in the editor.
>
> ![The same postcard written in font-2, a flowing joined-up cursive.](https://mintcdn.com/paperjoy/F1MJj4Vyrx0MCZIR/images/postcards/card-font-2-en.webp?fit=max\&auto=format\&n=F1MJj4Vyrx0MCZIR\&q=85\&s=cce44c23da64319bb07dc40e18d00d36)

### Natural mistake

Set `"mistake": true` to cross out one word and write it again, the way people do when they write by hand. It makes the card feel less printed. The default is `false`.

Paperjoy picks the word from the message itself, so the same text always gets the same correction. Messages with a single word, or with no suitable word, are written without one.

![A postcard where one word is scribbled out and written again right after it.](https://mintcdn.com/paperjoy/F1MJj4Vyrx0MCZIR/images/postcards/card-mistake-en.webp?fit=max\&auto=format\&n=F1MJj4Vyrx0MCZIR\&q=85\&s=8cedd02ca1c16d8de0adda3f3ed19af1)

## Signature

Pick one of two kinds. You can't send both on the same postcard.

> [card] Typed signature
>
> Send `signature` with up to 50 characters. It is written on a single line in the same handwriting as the message, so it must fit on one line.

> [card] [Custom signature](https://docs.paperjoy.co/en/postcards/custom-signatures.md)
>
> Send `signature_id` to use your real signature, traced from a scan. Available on Pro and Business plans.

You can also leave both out and end the message with your name.

## Writing tips

* **Use their name.** "Dear Anna" beats "Dear customer". Map the first name from your CRM or form.
* **Keep it to 2–4 sentences.** Short notes look natural in handwriting and always fit.
* **Say one specific thing.** Mention the order, the meeting, or the anniversary.
* **Skip links and codes.** Nobody types a URL from a postcard. A short, memorable word works better.
* **Stay friendly.** Every message passes an automated content check. Offensive messages are [rejected](https://docs.paperjoy.co/en/postcards/statuses.md#rejected) and the credit is returned.


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.