When a customer subscribes to a back-in-stock alert, should you notify them via email or SMS? The answer depends on your audience, your products, and your goals. Let's look at the data.
Email Back-in-Stock Alerts
The Numbers
- Open rate: 55–70% (vs. 20% for standard marketing emails)
- Click-through rate: 15–25%
- Conversion rate: 8–15%
- Cost per send: Near zero with most email platforms
Pros
- Free or very cheap to send
- Rich formatting (images, buttons, product details)
- Easy for customers to save and return to
- Higher acceptance — most people are comfortable sharing email
SMS Back-in-Stock Alerts
The Numbers
- Open rate: 95–98%
- Click-through rate: 25–35%
- Conversion rate: 12–20%
- Cost per send: $0.01–$0.05 per message
Pros
- Near-instant delivery and reading
- Highest open rates of any channel
- Perfect for time-sensitive restocks
- Hard to miss — lives in their text messages
When to Use Which
Use email when: You sell to a broad audience, margins are tight, and restocks aren't urgently time-sensitive.
Use SMS when: Products sell out quickly after restocking, you sell limited editions, or your audience is mobile-first.
Use both when: You want maximum recovery. Let customers choose their preferred channel at sign-up.
WhatsApp: The Third Option
In markets like Europe, Brazil, India, and Southeast Asia, WhatsApp is the dominant messaging platform. Offering WhatsApp restock alerts can dramatically increase subscription rates in these regions.
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Install Free on ShopifyThe best strategy? Offer all channels and let your customers choose. Multi-channel back-in-stock alerts consistently outperform single-channel approaches.
