Klaviyo back in stock alternative

A Klaviyo back-in-stock alternative that re-checks stock before it emails

Klaviyo’s back-in-stock flow sends when inventory ticks above zero. Back in Stock re-verifies live stock the moment it sends — so a shopper never gets emailed about something they still can’t buy — at a flat price, not billed per contact.

See the app →

by SlothRocket

how an alert fires (or doesn’t)

The ✕ hold branch is the whole reason the app exists.

Klaviyo is a full email & SMS marketing platform; back-in-stock is one flow inside it. This compares Back in Stock — a focused restock app — with that flow, as Klaviyo documents it.

How Back in Stock compares to Klaviyo (built-in flow)

	Back in Stock	Klaviyo (built-in flow)
Re-checks live stock before each send	✓	Not advertised
Flat price, not per-contact	$19/mo · unlimited	Contact-based
Turnkey restock setup (no flow building)	✓	Build a flow
Demand insights: what to restock	✓	General analytics

Competitor facts from its live Shopify App Store listing, as of August 2026. Pricing and features change — check the current listing. We only compare on what each app publicly states.

The real difference: it re-checks stock before it sends

Most restock apps fire on the inventory webhook. We re-check before we send.

An inventory webhook reports a quantity, not whether the product can be bought. That gap sends emails for things nobody can buy — wrong location, unpublished product, sold out again, wrong variant. Back in Stock re-verifies live stock at the moment it sends, and holds the alert if the item isn’t actually purchasable.

Why alerts fire falsely →

The verdict

Already running Klaviyo for all your marketing? Its back-in-stock flow will do the job. But if you want restock alerts that re-check the shelf before sending — and a flat price instead of one that climbs with every contact — that’s where Back in Stock is built to win.

Pricing

Free to start. Flat $19/month when you grow.

Back in Stock is a flat $19/month with unlimited alerts, plus a free plan to start — the price doesn’t grow with your contact list the way platform billing does.

Get it on the Shopify App Store →

Frequently asked questions

Does Klaviyo have a back-in-stock feature?

Yes — it's a built-in flow and signup form inside the Klaviyo platform (email/SMS). This page compares it with Back in Stock, a focused restock app.

Why use a separate app instead of Klaviyo's flow?

For accuracy and price. Back in Stock re-verifies live stock at the moment it sends, so it doesn't email shoppers about products that aren't actually buyable — and it's a flat $19/month, not billed by contacts.

Can I use both Klaviyo and Back in Stock?

Yes. Many merchants keep Klaviyo for marketing campaigns and use Back in Stock specifically for accurate restock alerts.

Does Back in Stock do email marketing campaigns?

No. It focuses on restock alerts. For broad email and SMS marketing, segmentation and campaigns, Klaviyo is the platform built for that.

How much does Back in Stock cost?

Free to start, then a flat $19/month for unlimited alerts. No per-contact fees.

Compare Back in Stock with other apps

Try the accuracy-first restock app →

Comparison compiled from public sources, as of August 2026. We only state what Klaviyo’s own listing advertises; where it does more than we do, we say so. Written by Luca, who builds SlothRocket.