> ## 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.

# Addresses and envelopes

> Format the recipient and Polish delivery address, and control the return address on the envelope.

Each postcard travels in a C6 envelope (162 × 114 mm), addressed by hand in the same font as the card.

![A handwritten envelope with the sender's company and address top left and the recipient Pani Anna Kowalska, ul. Marszałkowska 10 m. 4, 00-001 Warszawa in the middle.](https://mintcdn.com/paperjoy/F1MJj4Vyrx0MCZIR/images/postcards/envelope.webp?fit=max\&auto=format\&n=F1MJj4Vyrx0MCZIR\&q=85\&s=b730436957fe28abed5549ed6b1eaee3)

## Recipient

Send a person, a company, or both. At least `first_name` or `company_name` is required.

| Field | Example | Limit |
| - | - | - |
| `prefix` | `Pani`, `Pan`, `Dr` | 30 characters |
| `first_name` | `Anna` | 255 characters |
| `last_name` | `Kowalska` | 255 characters |
| `company_name` | `Studio Forma` | 255 characters |

```json theme={null}
{
  "recipient": {
    "prefix": "Pani",
    "first_name": "Anna",
    "last_name": "Kowalska"
  }
}
```

## Delivery address

Paperjoy delivers to addresses in **Poland** only.

| Field | Example | Rule |
| - | - | - |
| `line_1` | `ul. Marszałkowska 10` | Required. Street and building number. |
| `line_2` | `m. 4` | Optional. Apartment, floor, or c/o. |
| `postal_code` | `00-001` | Required. Two digits, a hyphen, three digits. |
| `city` | `Warszawa` | Required. |
| `country` | `PL` | Required. Always `PL`. |

```json theme={null}
{
  "address": {
    "line_1": "ul. Marszałkowska 10",
    "line_2": "m. 4",
    "postal_code": "00-001",
    "city": "Warszawa",
    "country": "PL"
  }
}
```

Because every address is domestic, the country line is not written on the envelope.

> [!WARNING]
>
> Paperjoy checks the format, not whether the address exists. Make sure the postal code matches the city and that apartment numbers are included. A postcard sent to a wrong address can't be recalled.

## Return address

The top left corner of the envelope shows your organization's name and address. By default, Paperjoy uses the company data from your invoices.

To print a different name or address, for example a shop instead of your registered office, open [**Ustawienia → Organizacja**](https://paperjoy.co/settings/organization) (Settings → Organization) and turn on **Użyj innych danych nadawcy na kopertach** (Use a different sender on envelopes). Your invoices are not affected.

![The Organization settings page with company details from the NIP lookup and the option to use a different sender on envelopes.](https://mintcdn.com/paperjoy/F1MJj4Vyrx0MCZIR/images/app/organization.webp?fit=max\&auto=format\&n=F1MJj4Vyrx0MCZIR\&q=85\&s=20120f085a494d9d1ee4a618669e6ded)

## Envelope layout

Paperjoy lays out every envelope to meet Poczta Polska rules:

* The stamp area in the top right corner (74 × 40 mm) stays empty.
* A 15 mm strip along the right and bottom edges stays empty.
* Long recipient lines move left instead of wrapping.

If the recipient or return address is too long to fit, Paperjoy rejects the postcard with a `422` error on `address`:

```json theme={null}
{
  "message": "The sender or recipient address does not fit on the envelope.",
  "errors": {
    "address": ["The sender or recipient address does not fit on the envelope."]
  }
}
```

Shorten the longest line, for example by abbreviating `ulica` to `ul.` or moving the apartment number to `line_2`.


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