Klaviyo vs FAST Alerts

Klaviyo: Email Marketing & SMS and FAST Alerts: Back in Stock are evenly matched on rating (4.7★ vs 4.8★) — the differentiator comes down to pricing fit, feature breadth, and which app's interaction pattern suits your team's workflow.

Pricing entry tiers: Klaviyo: Email Marketing & SMS at Free to install, FAST Alerts: Back in Stock at Free plan available. Check each app's tier structure for the capacity limits you actually need before deciding — the headline number is the same shape, but the gating shape per tier (seats, usage volume, integrations) varies.

Klaviyo: Email Marketing & SMS has the larger user base (3,292 reviews vs 9), which usually maps to broader integration coverage, faster bug-fix cadence, and a deeper bench of community workflow patterns. FAST Alerts: Back in Stock's smaller cohort can be an advantage for niche workflows where the bigger app has accumulated bloat.

Recommended evaluation path: install both apps' free tiers (where available) and run them in parallel on a small cohort for 7-14 days before committing. The data tables below show the per-feature breakdown — for most merchants the deciding factor will be a single integration or workflow detail that's hard to compare from listing pages alone.

This verdict is generated from the live marketplace data on this page — rating, review count, pricing tier, and category position all refresh from the canonical Shopify App Store listing every 24 hours. AppRanks does not accept payment to influence comparison outcomes; the methodology is documented on the About page and applies identically to every pair on the site.

Is Klaviyo: Email Marketing & SMS or FAST Alerts: Back in Stock cheaper?

Both Klaviyo: Email Marketing & SMS and FAST Alerts: Back in Stock offer paid plans only. Klaviyo: Email Marketing & SMS starts at Free to install; FAST Alerts: Back in Stock starts at Free plan available. Compare the per-tier features in the Pricing section above before committing.

Which has better reviews, Klaviyo: Email Marketing & SMS or FAST Alerts: Back in Stock?

Klaviyo: Email Marketing & SMS (4.7★, 3,292 reviews) and FAST Alerts: Back in Stock (4.8★, 9 reviews) are essentially tied on rating. Look at review velocity and individual reviewer quotes — both visible on each app's detail page — to differentiate.

Should I choose Klaviyo: Email Marketing & SMS or FAST Alerts: Back in Stock?

FAST Alerts: Back in Stock holds the higher average rating (4.8★ vs 4.7★). That is the one dimension AppRanks can separate them on here — read both apps' detail pages for the feature breakdown and recent listing changes.

Which is faster to set up, Klaviyo: Email Marketing & SMS or FAST Alerts: Back in Stock?

Both apps are one-click installs from the Shopify App Store. Klaviyo: Email Marketing & SMS has the deeper published review base (3,292 vs 9), which often — though not always — accompanies better-tested setup docs. AppRanks doesn't measure setup time directly: read the recent reviews on each app's detail page for user-reported install experience.

Which works better for small vs large Shopify App Store merchants?

Klaviyo: Email Marketing & SMS typically suits early-stage and growth-mode teams based on its published review base (3,292 reviews). FAST Alerts: Back in Stock typically suits early-stage and growth-mode teams based on its published review base (9 reviews). A larger review base generally means the app has been exercised at scale — relevant if you are processing high volume or handling enterprise compliance requirements.