---
title: "Send Returning Shopper events to Postscript (existing subscribers only)"
description: "Returning Shopper events for people already subscribed to your Postscript. Never adds contacts or texts anyone new."
url: https://wholayer.com/help/destination-postscript
---

# Send Returning Shopper events to Postscript (existing subscribers only)

> Returning Shopper events for people already subscribed to your Postscript. Never adds contacts or texts anyone new.

Category: Destinations

Included on the **Growth** plan and above.

## What it does
When a shopper comes back to your store and is **already your Postscript subscriber**, we send a **wholayer_returning_shopper** event with the products they viewed, at most once a day. That's all. We check they're subscribed first, we never add a contact or a phone number to Postscript, and we never text anyone who hasn't opted in with you. The event itself is free.

Your email platform receives new shoppers and decides what you're charged; see [Shopper ID guarantees](https://wholayer.com/help/shopper-id-klaviyo-guarantees).

## Connect it
1. In Postscript, open **Settings → API** and copy the **private** API key (it starts with `sk_`, not `pk_`).
2. Connect your email platform in WhoLayer first (for example Klaviyo). Postscript works alongside it.
3. In WhoLayer, open **Destinations**, choose **Postscript**, and paste the key. **Send test** only checks the key; it doesn't create anything.
4. Build a flow triggered by the custom event **wholayer_returning_shopper**.

## Good to know
- Postscript only gets Returning Shopper events for people who are already your SMS subscribers. We never add a phone number and never text anyone new.
- It works alongside an email platform (Klaviyo or another one above), which receives new shoppers and is used for billing.
- Postscript event names can't contain spaces, so the event is wholayer_returning_shopper.
- Opted-out people are never sent, and opt-outs take effect immediately.
- We encrypt your key when you save it and only ever show its last characters.

## Related

- [How Shopper ID works](https://wholayer.com/help/shopper-id-how-it-works.md)
- [Shopper ID and Klaviyo: what you're charged for, refunds, the daily cap, and the holdout](https://wholayer.com/help/shopper-id-klaviyo-guarantees.md)
- [Klaviyo schema: WhoLayer profile properties and events](https://wholayer.com/help/klaviyo-schema.md)
- [Your responsibilities when you use WhoLayer](https://wholayer.com/help/customer-obligations.md)