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

# Barcodes and NFC

> How passes are read at checkout — barcode formats, NFC, and dynamic barcode content

The bottom of the pass is where it gets *used*: either a **barcode** the store scans, or **NFC** so the customer just taps their phone. Configure both in the **Advanced** tab of the [template editor](/pass-templates/overview).

## Barcode or NFC?

* **NFC (tap to use)** — the pass works through a tap, like a payment card. Whether NFC is available depends on your program's setup (it requires NFC-capable terminals and certificates); when active, the pass shows a small tap icon instead of a barcode.
* **Barcode** — works with any scanner your stores already have. This is the default for most programs.

A pass shows one or the other, not both. Here is the same pass both ways, in Apple Wallet on an iPhone:

<Columns cols={2}>
  <Frame caption="NFC: a small tap icon in the corner, and the wallet asks the customer to hold the phone near the reader.">
    <img src="https://mintcdn.com/stell/C_zhUrQoTUQsZ2Th/images/wallet/iphone-front.png?fit=max&auto=format&n=C_zhUrQoTUQsZ2Th&q=85&s=734e06a8578ad224fdf67fa9c9367b13" alt="A pass with NFC enabled in Apple Wallet, showing a tap icon on the pass and the Hold Near Reader prompt below it" width="1320" height="2868" data-path="images/wallet/iphone-front.png" />
  </Frame>

  <Frame caption="Barcode: a QR code at the bottom of the pass, ready to scan.">
    <img src="https://mintcdn.com/stell/C_zhUrQoTUQsZ2Th/images/wallet/iphone-front-qr.png?fit=max&auto=format&n=C_zhUrQoTUQsZ2Th&q=85&s=262866a9ae10f6e25945e0e3e4107c40" alt="The same pass with a QR code at the bottom instead of the NFC tap icon" width="1320" height="2868" data-path="images/wallet/iphone-front-qr.png" />
  </Frame>
</Columns>

## Barcode formats

A template can hold up to 3 barcodes. Supported formats: **QR**, **PDF417**, **Aztec**, **Code 128**, **Code 39**, **Codabar**, **EAN-13**, and **Interleaved 2 of 5**.

Pick the format your POS scanners actually read — when in doubt, **QR** is the safest modern choice, and your POS supplier can confirm. Each barcode also takes an optional **alt text**, shown under the barcode so staff can type the code manually if scanning fails.

## Dynamic barcode content

The barcode **message** — what the scanner actually reads — supports the same `{{…}}` placeholders as [fields](/pass-templates/fields). This is how the barcode identifies the individual customer:

| Goal                                         | Message                                           |
| -------------------------------------------- | ------------------------------------------------- |
| Scan resolves to your CRM member number      | `{{customer.externalId}}`                         |
| Scan resolves to the customer's phone number | `{{customer.mobileNumber.national}}`              |
| Scan resolves to the Stell pass              | `{{passId}}` (the default when no message is set) |

Combinations work too — for example `{{customer.externalId}}-{{passId}}`. Whatever your POS looks up members by, that's what belongs in the barcode message.

## Encoding

The default encoding (ISO 8859-1) is right for almost everyone and what scanners expect. Switch to UTF-8 only if your barcode content needs characters outside Western alphabets — and confirm your scanners handle it.

## Also in the Advanced tab

* **Locations** — pin your stores' coordinates and the pass surfaces on the customer's lock screen when they're nearby. A relevance radius controls how close is "nearby".
* **Sharing** — prohibit sharing of the pass, or set a custom share URL and text.
* **Pass actions** — buttons on the pass on newer iPhones, for example a link to your site.