Side-by-side comparison · 24 data points
Sell preorders & backorders with full/partial payments. Auto send back-in-stock & coming soon alerts
| FlowSend ‑ Flow Mail App | Preorder, Back In Stock REZ | |
|---|---|---|
| Tagline | ||
| Description | ||
| Screenshots | images | images |
| Languages | ||
| Platforms | ||
| Developer |
Send customisable transactional emails via Flow using your own domain or SMTP provider
| Metric | FlowSend ‑ Flow Mail App | Preorder, Back In Stock REZ |
|---|---|---|
| Rating | 4.4 ★ | ★ 5.0 ★ |
| Total reviews | 4 | ★ 1.5k |
| Free plan | Yes | Yes |
| Pricing | Free to install | Free plan available |
| Built for Shopify | — | ★ Yes |
| Pricing tiers | 4 tiers | 4 tiers |
| Listed features | 5 | 5 |
| Featured placements | — | 2 |
| Languages | 56 supported | 24 supported |
| Listed since | Mar 2026 | May 2025 |
Based on the data on this page, Preorder, Back In Stock REZ is the stronger choice for most Shopify App Store merchants — 5.0★ vs FlowSend ‑ Flow Mail App's 4.4★ is a meaningful gap that usually reflects real product or support quality differences across the user base.
Pricing entry tiers: FlowSend ‑ Flow Mail App at Free to install, Preorder, Back In Stock REZ 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.
Preorder, Back In Stock REZ has the larger user base (1,533 reviews vs 4), which usually maps to broader integration coverage, faster bug-fix cadence, and a deeper bench of community workflow patterns. FlowSend ‑ Flow Mail App's smaller cohort can be an advantage for niche workflows where the bigger app has accumulated bloat.
Recommended by size: small/early-stage merchants who need fast install and low risk should default to Preorder, Back In Stock REZ; mid-market and enterprise merchants with specific feature requirements should evaluate both — FlowSend ‑ Flow Mail App's 4-review base may include the workflow context that matches your specific use case better than Preorder, Back In Stock REZ's broader-but-shallower coverage.
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.
Read each app's audit: FlowSend ‑ Flow Mail App audit • Preorder, Back In Stock REZ audit
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| Last updated | — | — |
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| Keyword | FlowSend ‑ Flow Mail App | Preorder, Back In Stock REZ |
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| #43 | #237 |
Not featured in any section recently.
Both FlowSend ‑ Flow Mail App and Preorder, Back In Stock REZ offer paid plans only. FlowSend ‑ Flow Mail App starts at Free to install; Preorder, Back In Stock REZ starts at Free plan available. Compare the per-tier features in the Pricing section above before committing.
Preorder, Back In Stock REZ has the higher average rating (5.0★ from 1,533 reviews) compared to FlowSend ‑ Flow Mail App (4.4★ from 4 reviews). Both are tracked daily by AppRanks, so the figures here update each refresh cycle.
Preorder, Back In Stock REZ holds the higher average rating (5.0★ vs 4.4★). That is the one dimension AppRanks can separate them on here — read both apps' detail pages for the feature breakdown and recent listing changes.
Both apps are one-click installs from the Shopify App Store. Preorder, Back In Stock REZ has the deeper published review base (1,533 vs 4), 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.
FlowSend ‑ Flow Mail App typically suits early-stage and growth-mode teams based on its published review base (4 reviews). Preorder, Back In Stock REZ typically suits early-stage and growth-mode teams based on its published review base (1,533 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.
Migration support varies by app and category. FlowSend ‑ Flow Mail App and Preorder, Back In Stock REZ both publish their export options on their marketplace listing pages (or in their support docs); some apps offer one-click import from competitors, others require CSV. The fastest check: search "import from FlowSend ‑ Flow Mail App" in each app's help center. AppRanks does not track migration tooling directly — this is a category-specific capability worth verifying before commitment.
