A/B Testing for Shopify
Test product pages, add-to-cart buttons, and storefront UX on your Shopify store. Stellar installs in your theme head, keeps pages fast with a 5.4KB script, and tracks conversions through checkout.
🚀 Trusted by Shopify store owners and growth teams
Set up A/B testing on your Shopify site in under 60 seconds
How it works on Shopify
Install the Stellar snippet
Add one line of code to your Shopify site head. Direct installation is recommended for anti-flicker and fastest variant delivery.
Create an experiment and variants
Use the no-code visual editor to change headlines, buttons, images, or layout on live pages—no redeploy required.
Configure targeting rules
Limit experiments to specific URLs, devices, or countries so tests only run for the audience that matters.
Add conversion goals
Track add-to-cart clicks, checkout starts, or completed purchases. For checkout attribution, use Shopify Custom Pixel—see our purchase tracking guide.
Analyze results and ship winners
Review real-time stats in Stellar, optionally sync conversions to GA4, and apply the winning variant.
Install the Stellar snippet on Shopify
Paste your snippet in theme.liquid inside the <head> tag. Direct head install is recommended so anti-flicker works correctly. Full install guide →
- In Shopify admin, go to Online Store → Themes
- Click Actions → Edit code on your live theme
- Open layout/theme.liquid
- Paste your Stellar snippet inside the <head> section, before </head>
- Save and preview a product page to confirm the script loads
Prefer direct head install over Google Tag Manager so anti-flicker works correctly on product and collection pages.
Pre-launch QA checklist
Run through this list before sending traffic to an experiment on Shopify.
- Confirm stellar.js loads in the Network tab on pages where experiments should run
- Verify only one install path is active (direct head install or GTM—not both)
- Match anti-flicker settings to your install method (direct install recommended)
- Clear CDN, theme, or platform cache after saving snippet changes
- Test in an incognito window with ad blockers disabled
- Verify stellar.js loads on product, collection, and cart pages (not just the homepage)
- Confirm the snippet is not duplicated in theme.liquid and GTM
- For purchase conversions, set up Shopify Custom Pixel per our purchase tracking doc
- After theme updates, confirm the snippet is still present in theme.liquid
Shopify limitations and gotchas
Checkout is sandboxed
Shopify checkout runs on Shopify-hosted pages. You cannot inject arbitrary scripts into checkout the same way as storefront pages. Use Shopify Custom Pixel for purchase conversion attribution.
Theme editor access required
Installing in theme.liquid requires theme edit permissions. If you use a theme app or agency-managed theme, coordinate snippet placement with whoever manages code changes.
App block and section caching
Heavy theme caching or delayed script loading can affect when variants apply. Direct head install and clearing Shopify CDN cache after changes reduces flicker.
GA4 tracking for Shopify experiments
Stellar sends conversion events to Google Analytics 4 via the Measurement Protocol, so experiment data appears alongside your other Shopify analytics. GA4 integration setup →
Event name: stellar_experiment_conversion
Register these custom dimensions in GA4 (Event scope):
experiment_id,experiment_namevariant_id,variant_nameconversion_id,conversion_name
Keep your Shopify site fast while you test
Stellar's 5.4KB async snippet loads without the bloat of legacy testing platforms—important for SEO and Core Web Vitals on Shopify.
At just 5.4KB and served on a CDN, Stellar's pure JS script is 25x smaller than competitors like VWO or AB Tasty. With minimal dependencies and a fixed size regardless of test count, it preserves your website's speed, Core Web Vitals, user experience, and SEO performance.
Why teams choose Stellar for Shopify
Shopify A/B test ideas to run first
Product page hero
Test hero images, headlines, and value props on your best-selling PDPs.
Product gallery order
Compare lifestyle vs. product-only image order for add-to-cart rate.
Add to cart button
Test button copy, color, and sticky ATC placement on mobile.
Pricing presentation
Compare showing compare-at price, bundles, or subscription options.
Social proof blocks
Test reviews placement, UGC carousels, or trust badges near the buy box.
Shipping messaging
Test free-shipping thresholds and delivery estimates above the fold.
Upsell modules
Test cross-sell carousels in cart drawer vs. inline on PDP.
Purchase conversion
Attribute completed orders to experiment variants with Custom Pixel tracking.
Pricing
Free
Up to 25k MTU
Built-in analytics
Visual web editor
Custom CSS & JS editor
AI editor assistant
Basic A/B testing
Up to 3 variants per experiment
Up to 2 experiments running simultaneously
Pro
50k MTU included
Unlimited variants
Unlimited concurrent experiments
Advanced targeting rules
Dynamic keyword insertion
AI insights & recommendations
Priority support
Enterprise
Custom MTU volume
Custom solutions
Integrations support
We dynamically bill in small increments of 1k MTU, so you only pay for what you actually use and never overpay
No hidden fees, no large fixed blocks. Scale smoothly as your traffic grows with predictable, usage-based billing
We only count users who actually see experiments. Multiple experiment views from the same user count as just 1 MTU
Trusted by marketers running experiments
Jake M. — Performance Marketer
⭐️⭐️⭐️⭐️⭐️
Other testing tools have a million features I don't need. Stellar focuses on what actually matters: speed, ease of use, and great analytics.
Richard R. — E-commerce Owner
⭐️⭐️⭐️⭐️⭐️
Stellar is the real deal. No unnecessary features, no steep learning curve. Just quick tests that actually improve our store.
Ben C. — Growth Hacker
⭐️⭐️⭐️⭐️⭐️
It does the job without slowing down our pages. If you're running tests and care about performance, this is the tool to use.
Frequently Asked Questions
More platforms
Stellar works on any site where you can add head code. Explore setup guides for other platforms: