Key takeaways
- There is no single “CRO app”. CRO is multiple jobs - reviews, A/B testing, cart upsells, popups, trust signals - each best served by a focused tool.
- The biggest hidden cost of a CRO stack is JavaScript weight. Five mediocre CRO apps stacked together can negate the lift they each provide.
- Audit your current stack before adding. Most stores are over-installed and under-using.
- Start with the highest-leverage gap: reviews if you don’t have them, then mobile experience (which is rarely an app), then upsells if your AOV is the bottleneck.
The best Shopify CRO stack for most stores is a reviews app, a native cart drawer and trust signals, Klaviyo forms for email capture, and an A/B testing tool once traffic allows. Fudge builds the storefront parts as native theme code.
Why you can trust us
We have spent four years inside Shopify. We build Fudge, the AI operator for Shopify stores, with a 4.9 rating on the Shopify App Store. Conversion is one of the goals it works on, and it writes the storefront side of these CRO improvements as native code. The recommendations below come from working inside hundreds of CRO stacks.
Best overall: Fudge
If you’re picking one app to anchor the stack, it’s Fudge, the AI operator for Shopify stores. Most “CRO apps” are SaaS widgets that inject JavaScript into your storefront and wait for you to know what to fix. Fudge works the other way round. Give it a conversion goal and it reads your Shopify orders and Google Analytics, finds the pages where shoppers drop off, ranks the fixes and builds them as drafts in your theme as native Liquid, JS, and CSS. Your team approves each change, and Fudge compares conversion rate and purchases before and after it goes live. No third-party script, no monthly creep, no rendering tax.
Jobs Fudge replaces in this stack:
- Cart drawer & upsells — built into the theme, not bolted on
- Popups & email capture — native components, fully styleable, connected to Klaviyo (which still sends the emails)
- Quizzes & recommendations — generated as native code with your products and brand context
- Bundle builder — offers on Shopify’s own discounts, no per-bundle SaaS fee
- Trust signals — already native code; Fudge writes them in
- Landing pages, PDP variants, seasonal campaigns — the broader CRO work most apps don’t touch
Where to pair Fudge with a specialist:
- Reviews — still pick a specialist (Judge.me, Yotpo, Loox, Okendo)
- A/B testing infrastructure — Fudge compares results before and after a change; pair it with Intelligems or Shoplift if you’re running structured experiments, and Fudge can build the variants for them
- Post-purchase upsells on the order status page — Shopify checkout extension territory
For most stores, that means Fudge + a reviews app + (optionally) an A/B tool is a complete CRO stack. The rest of this post is for filling the specialist gaps.
The jobs CRO apps do
- Reviews & social proof - review collection, display, syndication
- A/B testing - run experiments on PDP, cart, pricing
- Cart drawer & upsell - convert cart visits to checkouts and AOV
- Popups & email capture - convert traffic to email list
- Post-purchase upsell - increase AOV on the thank-you page
- Bundle builder - merchandise multi-product purchases
- Quizzes & recommendations - personalise the route to purchase
- Trust signals - usually native code, not an app
Most stores need 3-5 apps from this list, not all 8.
The top picks by job
Reviews
Judge.me, Yotpo, Loox, Okendo, Stamped.io. See our best Shopify review apps for the full comparison.
Pick by use case: Judge.me for budget, Yotpo for marketing stack, Loox for photo-led, Okendo for premium.
A/B testing
Intelligems, Shoplift, Convert, VWO. See our best Shopify A/B testing tools ranking and our A/B test guide.
Pick by test type: Intelligems for pricing/PDP element tests, Shoplift for theme-level swaps.
Cart drawer & upsells
- CartHook - cart drawer + upsell features.
Some themes ship with a decent cart drawer already; check before adding an app. The native cart drawer in Dawn, Sense and Craft handles the basics; upsells need a theme edit or an app.
Post-purchase upsells
- ReConvert - post-purchase upsells (after checkout, before thank-you).
- AfterSell - post-purchase upsells, alternative to ReConvert.
For ratings and prices, see our best Shopify post-purchase upsell apps comparison.
Popups & email capture
Klaviyo Forms, Privy, Optimonk. See our Shopify newsletter popup guide.
Klaviyo’s native forms are often enough if you’re using Klaviyo for email. Privy/Optimonk are heavier-weight popup tools.
Quizzes & recommendations
Octane AI, Shop Quiz, Quizify, Recomma, Quiz Kit. Plus AI builders that handle quizzes natively like Fudge’s quiz builder.
See our product recommendation quiz breakdown.
Bundle builder
Shopify Bundles (native, free), Bold Bundles, Rebuy.
Native Shopify Bundles is the right starting point. Bold or Rebuy for advanced merchandising or BFCM-style bundle promos.
Trust signals
No app needed. Native theme code (Liquid + CSS) is faster, cleaner, and doesn’t add JavaScript. See our trust badges guide.
A recommended starting stack
For a store under $1M revenue starting from scratch:
- Reviews: Judge.me (free tier)
- Cart drawer: native theme (no app)
- Trust signals: native theme (no app), see our guide above
- Email capture: Klaviyo Forms (if you’re on Klaviyo, otherwise a free-tier popup tool)
- Quiz: if your category fits (overlapping SKUs, personal-context-driven), Fudge-built quiz or Octane AI
Three apps, plus native theme features. Don’t stack more before the basic stack is producing measurable lift.
For a store $1M-$10M with operational complexity:
- Reviews: Yotpo or Okendo
- A/B testing: Intelligems
- Cart drawer + upsell: native + app combination (Rebuy or similar)
- Post-purchase upsell: ReConvert or AfterSell
- Email capture: Klaviyo Forms
- Quiz / recommendation: Octane AI or built natively
Six apps. Audit quarterly.
What we don’t recommend
Stacking three apps for the same job
Two cart-drawer apps doing similar things. Three email-capture apps fighting each other. Audit and consolidate.
Apps that promise generic “conversion lift” without naming the mechanism
If you can’t explain in one sentence what an app does to lift conversion, it probably isn’t lifting conversion. Cut.
Apps that don’t ship a free trial or free tier
Most CRO apps offer free trials. Tools that don’t are betting on stickiness, not value.
Apps with no analytics view of their own impact
If you can’t see whether the app is moving the metric, you don’t know if it’s worth the monthly fee. Demand attribution-aware reporting.
For the wider picture, see our Shopify CRO guide and 12 high-impact CRO tactics.
FAQ
How many CRO apps should I have installed?
Three to six. More than that and the JavaScript overhead starts to negate the lift each one provides. Audit quarterly.
What's the highest-impact CRO app?
Reviews, almost universally. Stores adding a review app for the first time often see a measurable lift on product pages. After reviews, A/B testing and post-purchase upsells are next.
Do I need an A/B testing app on Shopify?
Only if you have ~50,000+ monthly sessions on the pages you'd test. Below that, ship changes and watch the trend rather than running underpowered tests.
Are CRO apps worth the monthly fee?
The right ones are. A reviews app usually earns back a $30-100/month fee. The wrong ones aren't - apps that promise generic "lift" without a specific mechanism rarely earn back their fee. Audit individually.
Can I do CRO without apps?
Yes for trust signals, cart drawer, PDP changes, popups and quizzes - all of these can be native theme code, and Fudge builds them for you. Collecting reviews and running A/B tests still need an app.
