Test Shopify Changes With Rollouts and SimGym

You can now test a Shopify store change in two steps. Use SimGym to preview a new theme with simulated shoppers, then use Rollouts to show it to a slice of real visitors or schedule it for an exact moment. Together they replace the old habit of editing the live theme on Friday night and hoping.

Both features are tied to Shopify's Winter '26 Edition, published in December 2025. Coverage describes SimGym as a research preview and Rollouts as early access, so check what your own store can use.

1What is Shopify SimGym?

SimGym creates simulated shoppers that browse your store, move through collections, add items to the cart and leave qualitative feedback.

There are two simulation types, as coverage of the Winter '26 Edition describes them:

• Analyze a theme. You get prioritized recommendations to improve conversion.
• Compare two themes. It estimates which one will convert better. The winner is the theme with the higher add-to-cart rate.

You can point the simulated shoppers at one area, such as the home page, products, collections, cart or search.

What are its limits?

Shopify says simulated shoppers are not a substitute for real A/B testing, and results can differ from real buyer behavior. SimGym does not publish or schedule anything. It only tests.

Sources disagree on access and cost: some describe free trial credits, others a per-simulation charge afterwards. Check the current terms in your admin before running a batch.

2What is Shopify Rollouts?

Rollouts is a native place to schedule and test storefront changes. According to Shopify's changelog post, you can:

• schedule a theme change for an exact date and time, for a flash sale or seasonal launch;
• send a percentage of real visitors to a changed version and compare it with your current theme;
• set an end date for a limited promotion, after which the store reverts automatically.

Shopify's changelog says it is available on Basic plans and above, and coverage notes that the new version of Shopify Markets must be enabled. Market targeting is for Advanced and Plus plans. It was still early access in the coverage we found.

3A workflow we would use before a sale

1. Duplicate your theme. Make the change in the copy, never on the live one.
2. Run Compare two themes in SimGym. Look at the recommendations, not just the winner. Treat them as a to-do list for a human to judge.
3. Fix the obvious problems. Cart friction and unclear shipping messages come up most often in this kind of review.
4. Create a Rollout for a small share of traffic. Start low. Watch conversion, checkout starts and support messages for a few days.
5. Widen it, or roll back. If numbers hold, increase the share.
6. Schedule the sale theme and its end. Set both times in advance so nobody has to be awake at midnight.

Simulated shoppers are not customers. The honest value is catching confusing layouts before they cost you, not proving that a change will lift revenue. We would not trust a single SimGym verdict to ship a redesign.

4What should you measure during a rollout?

Pick two or three numbers before you start and write them down: add-to-cart rate, checkout starts and completed orders. Add one check that is not a number, such as reading the support inbox for confusion about shipping or returns. Compare the rollout group with the rest of your traffic over the same days, so a weekend or a newsletter does not fool you.

5FAQ

Do I need Shopify Plus?

Not for Rollouts: Shopify's changelog lists Basic plans and above. SimGym availability has varied between reports, so check your admin.

Is SimGym a replacement for A/B testing?

No. It works with no traffic, which makes it useful for small stores, but it is a simulation. Real visitors in a Rollout tell you more.

Can I schedule a theme to switch back?

Yes. Rollouts can revert the store automatically when a campaign ends.

For more store tooling, browse the E-commerce & Retail hub, or list your shop in Discover so other founders can find it.

Pick one change you were going to make anyway this month, and run it through both steps before it goes live.