Instant publishes layouts as theme files on your Shopify store. By default they go to your live theme — the one shoppers see right now. On the Pro plan and up, you can publish to a draft theme instead to test changes before they go live.
The publish target
Every project has one publish target theme, chosen in Settings → Shopify under Publishing. All future publishes go to that theme until you change it.
When no theme is selected, Instant publishes to your live theme, and the helper text reads "Instant will publish layouts to the live theme."
When you pick a specific theme, the helper text reads "Instant will publish layouts to this theme."
In the theme dropdown, your live theme is grouped under a Live theme heading, and every other theme appears under All themes.
Draft themes require Pro
Selecting a draft theme requires the Pro plan or higher. On Free and Starter, the draft themes in the picker are disabled and marked with a Pro badge; hovering it shows "Upgrade to select draft themes." Publishing to a draft theme lets you:
Test layouts without affecting shoppers
Prepare a full theme before switching it live
Review designs on a Shopify preview link
Change the publish target
Open Settings → Shopify.
In the Publishing section, open the theme selector.
Choose your target theme.
Instant confirms with a toast: "Layouts will be published to the "{theme name}" theme," or "Layouts will be published to the live theme" when you switch back to live.
Publish to a draft theme
Once a draft theme is selected:
Build and finalize your layout.
Click Publish as usual.
Instant deploys to the draft theme, not the live storefront.
Use View live page from the publish menu to preview — for pages and blog posts it opens the URL with the theme's preview parameter, so you see the draft theme's version.
Draft-theme layouts aren't visible to shoppers until you make that theme live in Shopify, or switch Instant's target back to the live theme and republish.
Switching themes
When you change the target theme, previously published layouts stay on the old theme — they don't move automatically. To sync layouts to the new theme:
Select the new theme in Settings → Shopify.
Go to Published layouts → Republish all.
Instant redeploys every published layout to the selected theme.
You can also republish individual layouts one at a time.
Instant Embed on your target theme
Instant Embed must be enabled on whichever theme you publish to — live or draft. Instant checks for it during publish and prompts you if it's missing; from that prompt, Enable in Shopify opens the theme editor for the target theme so you can turn the embed on and save.
Making a draft theme live
Instant publishes layouts to a theme; it does not change which theme is live in Shopify. To make a draft theme your live storefront:
Finish publishing all layouts to the draft theme.
In Shopify admin, go to Online Store → Themes.
Publish that theme to make it live.
Alternatively, switch Instant's target back to the live theme and republish.