# Legacy (slower) ways to add customers

{% hint style="warning" %}
These steps are no longer recommended because they're slow or require a second barcode scanner. To add customers to the POS cart faster and more reliably, please use the new ["Add customer" POS UI extension](add-customers-to-the-pos-cart).
{% endhint %}

There are two different routes to add customers to the POS cart. Each comes with some PROs and CONs.

1. Since [the "Add customer" Smart Grid action](legacy-slower-ways-to-add-customers/shopify-pos-add-customer-smart-grid-action) is already built into Shopify POS and doesn't require loading the app, it's **the quickest method**. However, it requires a second barcode scanner. Also, it doesn't work with [custom barcodes synchronised with the app](synchronise-merchant-issued-custom-barcodes-with-the-app).
2. [The app's Smart Grid actions](legacy-slower-ways-to-add-customers/the-apps-smart-grid-actions) work with custom barcodes and auto-generated QR codes. The app's smart grid actions can scan with a mobile device's camera or a second barcode scanner. However, since the app is not natively built into Shopify POS, it loads slower, which may be very noticeable on older and less performant devices.

{% hint style="info" %}
Learn how to [customise your Smart Grid](https://www.youtube.com/watch?v=JP8rqSYlgVI).
{% endhint %}
