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

# Viewed Product Is Back in Stock Flow

Send a campaign to a customer when a product they recently viewed becomes available again. This flow brings shoppers back to items they showed real intent on, right at the moment those items are buyable.

## Before you start

Before you build the flow itself, prepare the campaign you want to send when the trigger fires.

<Steps>
  <Step title="Create an automated campaign">
    Create an automated campaign in the channel you plan to use: email, SMS, Viber, mobile push, or web push.
  </Step>

  <Step title="Insert the viewed product">
    Use the `ProductView` parameter to render the viewed product inside the campaign, or build the content in the new editor, which lets you pull in the product without configuring parameters manually.
  </Step>
</Steps>

<Tip>
  You can also add a block of related items or personalized recommendations so the customer has something to fall back on if the original product is no longer the best fit.
</Tip>

## How the trigger works

The flow launches on the **Viewed Product Changed — Product Returned to Availability** event.

<Info>
  * The trigger fires **every time** a product transitions from out of stock back to in stock. If a product cycles in and out of availability, each return to stock can trigger the flow again.
  * The trigger fires **per product**. If several products that a customer viewed come back in stock at the same time, the flow runs separately for each one.
</Info>

Because of this behavior, you should add frequency caps and delays so a single customer does not receive a burst of messages at once.

## Build the flow

<Steps>
  <Step title="Add the trigger">
    Set the flow to start on the **Viewed Product Changed — Product Returned to Availability** event. Apply a per-customer frequency cap so the customer cannot enter the flow multiple times in parallel.
  </Step>

  <Step title="Restrict send times">
    Add a condition that prevents the campaign from going out at night. If you run other product-availability campaigns in parallel, add a delay so this flow does not collide with them.
  </Step>

  <Step title="Validate the product view and stock">
    Add filters that confirm:

    * The product view happened recently (so you don't message customers about something they looked at months ago).
    * The product is currently in stock at the moment the campaign is about to send.
  </Step>

  <Step title="Check subscription and contact data">
    Confirm the customer still has an active subscription for the channel you're using and that you have valid contact information (email address, phone number, push token, etc.) for that channel.
  </Step>

  <Step title="Send the campaign">
    Send the prepared campaign. Optionally include related products or personalized recommendations alongside the viewed product.
  </Step>
</Steps>

## Notes on cost and pacing

<Warning>
  Because the trigger fires per product and on every return to stock, an unfiltered flow can generate a large volume of sends. Use the recency filter on the product view, the stock check, the nighttime restriction, and the per-customer frequency cap together to keep volume reasonable and to protect customer experience. Sending costs are billed in \$ based on your channel pricing.
</Warning>

## Recap

A well-built "Viewed Product Is Back in Stock" flow includes:

* An automated campaign prepared in your chosen channel with the viewed product rendered inside it.
* The **Viewed Product Changed — Product Returned to Availability** trigger with a per-customer frequency cap.
* A nighttime restriction and a delay to coordinate with other availability flows.
* Filters confirming a recent product view and current stock.
* A subscription and contact-data check for the channel.
* The send step, optionally enriched with related products or recommendations.