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The Back-in-Stock module converts inventory gaps into a recoverable revenue opportunity. When a product variant is out of stock, customers can subscribe through a storefront widget using their WhatsApp number. The moment that variant is restocked in Shopify, Galantis detects the inventory change and dispatches a WhatsApp notification automatically — no manual work, no delay, no missed restock window. The module has two distinct parts that work together: the storefront widget, which captures subscriptions on your live store, and the notification pipeline, which listens for restock events and sends the message. Both must be configured for the full flow to work.

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How it works end to end

Customer visits out-of-stock product page
  → Widget appears on the variant
  → Customer submits their WhatsApp number
  → Subscription created with ACTIVE status
  → Variant restocked in Shopify
  → Shopify sends products/update webhook
  → Galantis detects inventory_quantity 0 → > 0
  → BACK_IN_STOCK automation trigger fires
  → WhatsApp notification sent to all ACTIVE subscribers
  → Subscription status moves to NOTIFIED

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What this section covers

  • Installing and verifying the storefront widget
  • Customizing widget appearance and branding
  • How subscriptions move through their lifecycle
  • The full notification pipeline from restock detection to message dispatch
  • Per-variant product and inventory rules
  • Analytics and conversion metrics

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Guides in this section

Widget Installation

Script tag injection, verification steps, and troubleshooting widget display issues.

Widget Design

All branding and appearance settings — button, modal, colors, fonts, and form states.

Subscription Lifecycle

PENDING, ACTIVE, NOTIFIED, and CANCELLED — how subscriptions transition between states.

Notification Logic

The full pipeline from Shopify restock webhook to WhatsApp message dispatch.

Product & Inventory Rules

Per-variant subscription behavior, subscription limits, and eligibility rules.

Analytics

Active subscriptions, notification volume, click rate, conversion rate, and revenue attribution.

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Prerequisites

Before the Back-in-Stock module can send notifications:
  • Your WhatsApp Business Account must be connected — see WhatsApp Connection
  • An approved WhatsApp template must exist for the restock notification message — see Templates
  • The write_script_tags Shopify permission must be granted — required for widget injection
Subscription capture (the widget) works independently of the notification template — customers can subscribe before the template is approved. But notifications will not send until an approved template is in place and assigned to the Back-in-Stock automation flow.

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Billing

Back-in-Stock is billed as a separate add-on with two components: a monthly tier subscription that determines how many subscribers you can hold (Starter $19 / 250 subs → Enterprise $149 / 10,000 subs), and 1 Conversation credit per delivered notification drawn from the same credit pool as campaigns. Enterprise core plan includes the Starter BIS tier (250 subscribers) by default. See Back-in-Stock Add-on Billing for the full pricing breakdown.