The Klaviyo back in stock flow for Shopify stores that sell out

Why this flow beats everything else

Every other flow guesses at intent. Back in stock doesn't. The subscriber selected a specific variant, handed over their email for that one item, and is actively waiting. On limited-stock niche products I regularly see conversion rates several times higher than a welcome series, from a fraction of the volume.

The catch is that it's also the flow most likely to be left on Klaviyo's default settings — one email, delayed by quiet hours, sent to everyone whether the item restocked with two units or two hundred.

Setting up the trigger in Klaviyo

1. Enable back-in-stock in Klaviyo and add the sign-up button to your Shopify product template, including on sold-out variants — not just sold-out products.
2. Create a flow triggered by the Back in Stock metric so it fires when inventory crosses above zero.
3. Add a flow filter excluding anyone who has placed an order containing that item since subscribing, so buyers stop receiving reminders.
4. Set smart sending off for the first email on scarce items, and use a conditional split on inventory quantity to decide whether the urgency track runs.
5. Turn on the flow in live mode and check the first restock manually before trusting it.

The three-email structure

Niche angles that lift conversion

• Reef & aquarium: name the exact species or morph, state the arrival batch date, and add a one-line acclimation note. Buyers hesitate on livestock — remove the hesitation in the email, not on the product page.
• Outdoor, camping & 4WD: restocks are usually size, fitment or vehicle-specific. Reference the variant they subscribed to so a tourer isn't reading about a different rack system.
• Specialty pets & animals: link the restock to feeding, breeding or seasonal cycles. 'Back for the winter breeding run' converts better than 'back in stock'.
• Any niche: if the item ships from a single AU warehouse, say the cut-off time for same-day dispatch. Freight certainty closes enthusiast buyers.

Australian timing notes

Set your Klaviyo account timezone to your primary market — usually AEST/AEDT — and remember your list spans three to four time zones. For scarce stock, send immediately regardless of hour: a Perth subscriber waking to a sold-out alert is worse than an evening email. For deep restocks, a 9am to 8pm AEST window is plenty.

Watch public-holiday freight gaps too. If dispatch pauses for four days, say so in the email rather than letting the customer discover it at checkout.

Mistakes I see most often

• One email only — leaving roughly half the recoverable revenue on the table.
• Quiet hours delaying alerts on items that sell out in under two hours.
• Faking scarcity on deeply stocked products, which teaches the list to ignore you.
• No sign-up button on out-of-stock variants, so the list never grows.
• Never suppressing subscribers who've ignored five alerts for the same item.

FAQ

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