Shoplift runs your tests.
Spar fills the roadmap that feeds it.
Shoplift is one of the best ways to run a Shopify A/B test: native Liquid variants, no flicker, Bayesian results matched 1:1 to real orders. It does not decide what to test, rank your roadmap by revenue impact, or write the variant from your store's evidence. Spar does that upstream work, then runs the test itself or hands it to the runner you already have.
Shoplift owns the last stage. The roadmap that feeds it is the other three.
Every experiment moves through find, prioritize, build, then run and measure. Shoplift is excellent at running and measuring. The stages before it are where programs stall, and where Spar lives.
What is actually underperforming, and where is the money?
Which fix is worth running first?
Turn the idea into a working variant.
Split traffic, declare a winner, ship it.
A great runner does not fix an empty roadmap. Spar fills stages 1 to 3; your runner ships stage 4.
Two different kinds of product
The core difference: Shoplift executes and measures the tests you define, while Spar finds, ranks, and drafts the tests in the first place, then runs them or hands them to a runner. These rows capture differences in kind, well past a feature checklist.
Keep Shoplift. Put Spar in front of it.
If you love Shoplift's execution, you do not have to replace it. Spar sits upstream and keeps the runner fed, so your team is never staring at a blank editor wondering what to build next.
Connect and audit
Spar connects Shopify, GA4, Microsoft Clarity, reviews, and customer feedback, then audits your storefront against a rules library.
Rank by revenue
It ranks the opportunities by evidence strength and expected revenue impact, so you start with the test most likely to move money.
Draft and approve
Spar drafts the hypothesis and the variation code from the evidence. You review, edit, and approve before anything ships.
Launch in your runner
Spar runs it via its theme app extension, or you recreate the pre-drafted test in Shoplift and ship it with the native, no-flicker delivery you already like.
Spar's wired delivery integrations today are Convert, GrowthBook, and Intelligems. With Shoplift, the workflow is that Spar produces the ranked, evidence-backed, pre-written test and you recreate and launch it in Shoplift.
Pick the one that matches your bottleneck
If you've decided exactly what to test and you want it live in your theme with zero flicker, Shoplift is one of the best ways to run it. If the problem is figuring out what is worth testing in the first place, that's a different job.
Pick Shoplift if
- You already have a clear, well-prioritized list of what to test and just need to run it.
- Native, in-theme delivery with zero flicker is your top requirement. Winners become real Liquid sections in your own theme with no lock-in.
- Your team is comfortable building variants by hand in the Shopify Theme Customizer.
- You mainly run theme, section, template, and merchandising tests and want Shopify-matched conversion reporting.
- You want a proven, Shopify Plus Certified, highly rated standalone runner.
Shoplift is the first A/B testing app in the Shopify Plus Certified App Program and holds 4.9 stars across 125 Shopify App Store reviews.
Pick Spar if
- You keep running out of good, evidence-backed things to test. Your roadmap is the bottleneck, well before your runner.
- You want your store audited against a rules library and opportunities ranked by revenue impact rather than chosen by gut.
- You want GA4, Clarity, reviews, and customer feedback synthesized into hypotheses, with the variation code drafted for you to review and approve.
- You're an agency that needs a multi-client workspace and auto-drafted weekly client digests.
- You want the flexibility to run tests yourself or deploy through Convert, GrowthBook, or Intelligems, including keeping Shoplift downstream.
Pick both if
You love Shoplift's execution but need an engine to keep it fed. Spar finds, ranks, and drafts; Shoplift ships.
Questions buyers ask
Shoplift facts and how Spar's job differs.
See what Spar would put in your test queue
See the example site live, with the ranked, evidence-backed tests Spar built for it. Run them in Spar, or take them to Shoplift.