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Back in Stock Notifications for Klaviyo

Product availability alerts integrated with Klaviyo email marketing platform.

Overview​

Back in Stock Notifications for Klaviyo allows customers to sign up for email alerts when out-of-stock products become available again. The plugin integrates directly with Klaviyo's email marketing platform, capturing customer interest in unavailable products and automating notification flows when inventory is replenished.

Current Version: 1.3.4
Requires: WordPress 4.7+, PHP 8.0+, WooCommerce
Text Domain: back-in-stock

Key Features​

Customer Notification Forms​

  • Automatic Form Display — Shows signup form on out-of-stock products
  • Email Capture — Collects customer email addresses
  • Product Tracking — Links subscribers to specific product/variant SKUs
  • AJAX Submission — Seamless form submission without page reload

Klaviyo Integration​

  • List Management — Adds subscribers to Klaviyo lists
  • Event Tracking — Sends back-in-stock events to Klaviyo
  • Profile Creation — Creates or updates Klaviyo profiles
  • Custom Properties — Attaches product metadata to subscriber profiles

Product Feed Generation​

  • XML Feed Export — Generates product catalog feed for Klaviyo
  • Automated Updates — Scheduled feed regeneration via cron
  • Stock Status Tracking — Real-time inventory availability
  • Product Metadata — Includes images, prices, URLs

WooCommerce Integration​

  • Stock Level Monitoring — Watches inventory changes
  • Product Variation Support — Handles variable products
  • Out-of-Stock Detection — Automatically detects when products sell out
  • Restock Detection — Identifies when products return to stock

Notification Triggers​

The plugin fires events that Klaviyo flows can use to send emails:

  • Customer Subscribes — When user signs up for notifications
  • Product Restocked — When out-of-stock product has inventory
  • Reminder Emails — Follow-up reminders if product stays in stock

How It Works​

Sign-Up Flow​

Customer Views Out-of-Stock Product
    ↓
Form Displays on Product Page
    ↓
Customer Enters Email Address
    ↓
AJAX Submit to WordPress
    ↓
Plugin Sends to Klaviyo API
    ↓
Profile Created/Updated in Klaviyo
    ↓
Confirmation Message Displayed

Notification Flow​

Product Stock Level Changes
    ↓
WooCommerce Hook Fires
    ↓
Plugin Detects Restock Event
    ↓
Query Subscribed Customers
    ↓
Send Event to Klaviyo
    ↓
Klaviyo Flow Triggers
    ↓
Email Sent to Subscribers

Architecture Overview​

Frontend Component (Form)
    ↓
REST API Endpoint
    ↓
Klaviyo API Client
    ↓
Product Data Collector
    ↓
Feed Generator

Use Cases​

  • Demand Capture — Collect email addresses for popular out-of-stock items
  • Sales Recovery — Convert interested customers when stock returns
  • Inventory Insights — Identify high-demand products
  • Email List Growth — Build Klaviyo subscriber lists organically
  • Customer Experience — Reduce frustration from out-of-stock items

Technical Requirements​

  • WordPress 6.4 or higher
  • WooCommerce 8.0 or higher
  • PHP 8.0 or higher
  • Active Klaviyo account
  • Klaviyo API credentials (Private API key)
  • Laravel Mix for asset compilation

Klaviyo Configuration​

Required Klaviyo Setup​

  1. API Key — Private API key from Klaviyo account
  2. List ID — Klaviyo list for back-in-stock subscribers
  3. Flow Setup — Create Klaviyo flow triggered by restock event
  4. Email Template — Design notification email in Klaviyo

Klaviyo Events​

The plugin sends these events to Klaviyo:

  • Back in Stock Requested — When customer subscribes
  • Product Back in Stock — When product restocked
  • Notification Sent — Tracking for email delivery

Form Customization​

The subscription form can be styled and positioned via:

  • CSS Customization — Target form classes
  • Template Override — Override form template in theme
  • Shortcode Placement — Manual form placement with [back_in_stock_form]
  • Hook-Based Injection — Use WordPress hooks for custom placement

Data Structure​

Subscriber Data Stored in Klaviyo​

{
  "email": "[email protected]",
  "properties": {
    "product_sku": "PROD-123",
    "product_name": "Product Name",
    "product_url": "https://site.com/product/",
    "product_image": "https://site.com/image.jpg",
    "product_price": "49.99",
    "subscribed_at": "2026-04-20T14:30:00Z"
  }
}

Build System​

The plugin uses Laravel Mix for asset compilation:

  • JavaScript: src/js/ → dist/js/
  • SCSS: src/scss/ → dist/css/
  • npm Scripts: dev, prod, watch