A merchant reviewer wrote the app "only functioned as it should for about one month in total" across more than a year of use, called it "super expensive," and described chat support as "very unresponsive."
Comparison · Amp alternative
An Amp alternative where the send counts match the price tag.
Amp Back in Stock | PreOrder is the oldest app in the category and best for merchants who also need preorders. For alerts alone, its listed plans include 50 to 500 notifications a month. Kelso's $14 plan includes 750.
Sourcing: competitor pricing and review excerpts below were taken from Amp's public Shopify App Store listing and review pages in July 2026. At that time Amp showed a 4.9 star rating across 885 reviews and carried the Built for Shopify badge. Pricing changes; check their listing for current numbers.
Pricing, side by side
| Amp | Kelso | |
|---|---|---|
| Free plan | 10 notifications/mo, unlimited signups | 50 sends/mo, unlimited subscribers |
| Entry paid plan | $19/mo · 50 notifications | $14/mo · 750 sends |
| Mid tier | $29/mo · 100 notifications | $29/mo · 3,000 sends |
| Top listed tier | $49/mo · 500 notifications | $59/mo · 10,000 sends |
| Preorders | Included on paid tiers | Not offered |
| Revenue share or overage fees | None listed | None, ever |
Amp pricing as listed on the Shopify App Store, July 2026. Kelso pricing is current and listed in full on the pricing page.
Why merchants switch
These are paraphrased from dated, public one-star reviews on Amp's Shopify App Store review page. They are individual merchant reports, not our claims about every merchant's experience.
Another reviewer reports that for a majority of the months they used it, the back in stock function "has not worked/showed on the site."
Another reviewer wrote: "Stay away from this app - there are 10 other apps doing the same thing for a fraction of the price."
What Kelso does differently
- Volume that matches the price. Kelso's $14 plan includes 750 sends. Amp's listed $49 plan includes 500 notifications.
- A widget built for both theme generations: an OS 2.0 app block plus a legacy-theme snippet fallback, so it renders whether your theme is new or old.
- Two-path restock detection (webhook plus reconciliation poll) so alerts fire when stock actually returns.
- A full send audit log: queued, sent, delivered, clicked. You can verify the app is working instead of taking it on faith.
- Email support answered by a human in hours, with the response commitment published on our support page.
Where Amp may still fit
A fair comparison cuts both ways. Based on the same public listing:
- Amp bundles preorders with back in stock alerts. Kelso does not do preorders. If preorders are core to your store, Amp or a dedicated preorder app may fit better.
- Amp offers SMS notifications at a flat per-message price. Kelso is email-first and does not offer SMS yet.
- Amp holds a 4.9 star rating across 885 reviews, carries the Built for Shopify badge, and has operated since 2011, longer than any other app in the category.
Switching takes one CSV.
Export your waitlist from Amp, upload it once Kelso is live, and your subscribers carry over. Stuck on the export? Email us and a person will help.