Convert is the test runner. Spar is the experimentation program that feeds it.
Convert Experiences is a strong, privacy-first A/B testing platform, but someone still has to find the opportunity, prioritize it, and write the variant before any test exists. Spar does that upstream work as software: it audits your Shopify store, ranks opportunities by revenue, and drafts the variation code for your approval, then ships it itself or deploys through Convert. Keep your runner; add the brain that feeds it.
Convert runs the test. Something has to design it first.
An experimentation program runs Find, Prioritize, Draft, Run, Measure. Convert is strong from Run onward. The three stages before it are simply out of scope, so they fall on your team. Spar fills them, then hands the finished test to Convert or ships it itself.
You bring this
No storefront audit, no GA4 + Clarity + reviews synthesis.
Your analyst decides
No revenue-ranked queue of what to fix first.
You author the variant
Visual and code editors to build it; you write the variant.
Convert runs it
Visual + code editor, 40+ targeting, server-side and full-stack.
Convert measures it
Frequentist, sequential, and Bayesian stats. Privacy-first.
Audits and synthesizes
Crawls your store against a rules library, reads GA4, Clarity, reviews, feedback.
Ranks by revenue
An evidence-weighted queue of the highest-impact opportunities.
Drafts the code
Writes the hypothesis and the variation code. You review and approve.
Ships it
Shopify theme app extension natively, or deploys through Convert.
Declares winners
Spar runs and measures its own tests, winners declared with sequential statistics.
The overlap at Run and Measure is the point: keep Convert as the runner you already trust, and let Spar produce the evidence-backed, revenue-ranked, ready-to-ship tests that feed it.
Convert vs Spar, by what each one actually is
Convert is a general-purpose A/B testing platform your team operates. Spar is the AI CRO program that finds, prioritizes, and drafts the tests, then ships them itself or through Convert. The rows below are differences in kind rather than feature checkboxes.
Convert Experiences
Spar
Convert Experiences
A general-purpose A/B testing platform a team operates.Spar
An AI CRO program that audits, prioritizes, drafts, and ships, for Shopify.Convert Experiences
You or your analyst bring it; Convert executes it.Spar
Generated from connected GA4, Clarity, reviews, and feedback, audited against a rules library.Convert Experiences
Manual. No built-in revenue-ranked queue.Spar
Opportunities ranked by evidence strength and revenue impact.Convert Experiences
Visual editor plus code editor; you or your developer write the change.Spar
Drafts the variation code from the evidence; you review, edit, and approve before launch.Convert Experiences
Generic tracking script or theme app extension for a general tool; works on any site.Spar
Shopify theme app extension natively, or deploy through Convert, GrowthBook, or Intelligems.Convert Experiences
A multi-engine stats lab the analyst configures: fixed and sequential frequentist plus Bayesian.Spar
Spar runs and measures its own tests, winners declared with sequential statistics as part of the managed loop.Convert Experiences
Multi-client projects and a partner program; the cross-client summary dashboard is a noted gap.Spar
Multi-client workspace with auto-drafted weekly client digests.Keep your runner. Add the brain that feeds it.
Coexistence over rip-and-replace. Spar sits upstream of Convert and produces the tests, so you add throughput at the front of the funnel without re-platforming your running experiments or losing Convert's stats and privacy posture.
Connect and audit
Spar connects Shopify, GA4, Microsoft Clarity, reviews, and customer feedback, audits your storefront against a rules library, and ranks opportunities by evidence strength and revenue impact.
Draft and approve
For each opportunity, Spar writes the hypothesis and the variation code. You review, edit, and approve. Nothing goes live without your sign-off.
Ship through Convert or Spar
Deploy approved tests through Convert to keep its runner, multi-engine stats, and privacy posture, or ship on Spar's own Shopify theme app extension. Winners are declared with sequential statistics.
Prefer one system end to end? Spar can run delivery itself, in which case its theme app extension (on Shopify) or embed script (anywhere else) replaces Convert.
They solve different halves of the same job
Convert is the better choice when the test runner is your need and your privacy bar is high. Spar is the better choice when the work before the test is the bottleneck. Often the answer is both.
Pick Convert if
- Privacy or compliance is the deciding factor (EU, healthcare, regulated) and you want a vendor whose whole brand is GDPR/CCPA/HIPAA-ready with no data reselling.
- You need server-side and full-stack experiments, feature flags, or personalization, going beyond front-end storefront and marketing-page tests.
- You already have analysts who generate hypotheses and developers who build variants; your bottleneck is the runner rather than the front of the funnel.
- You want transparent, flat pricing with every feature in every plan and no per-feature gating.
Pick Spar if
- You are a Shopify brand or agency and the bottleneck is before the test: finding opportunities, reading GA4/Clarity/reviews, prioritizing, and writing variant code.
- You want a ranked, evidence-backed, revenue-weighted test queue instead of a blank editor.
- You want the variation code drafted for you, with a human approval gate before anything goes live.
- You are an agency that wants auto-drafted weekly client digests and per-client throughput, going beyond multi-client projects.
- You want storefront and marketing-page tests handled for you (on Shopify natively or via embed elsewhere) and are fine keeping checkout, subscription, and in-app internals with your engineers.
- You want to keep Convert and add the upstream brain: Spar can deploy through Convert.
Questions Convert buyers ask
Keep Convert. Add the program that feeds it.
Connect Shopify, GA4, and Clarity, and Spar will audit your store and return a ranked, evidence-backed queue of tests, with the variation code drafted for your approval. Ship them through Convert or on Spar's own Shopify extension.