Shopify's Block and Partial Tags: A Developer Preview Worth Paying Attention To

30 July 2026

Shopify just opened a developer preview for two new Liquid tags, {% block %} and {% partial %}, and unlike a lot of preview features, this one is aimed squarely at a pain point every theme developer already knows: page structure being scattered across JSON templates, sections, and snippets instead of living in one place you can actually read.

The block tag

{% block %} lets you compose a page from reusable pieces directly inside the template itself, the same way {% render %} lets you drop in a snippet. Blocks render markup from the blocks/ directory and still support theme editor settings, so merchants keep the customisation they’re used to. The difference is where the page structure lives: instead of a JSON template pointing at a list of sections that you then have to cross-reference against separate schema files, you can open a single Liquid template and read it top to bottom to see exactly how the page is built.

Anyone who’s built a custom theme with a non-trivial number of sections knows the current alternative: jumping between the JSON template, the section file, and its schema block just to answer “what actually renders on this page, and in what order.” This collapses that into one file.

The partial tag

{% partial %} marks a region of a page that JavaScript can fetch and swap out for freshly server-rendered HTML, without a full page reload. The documentation’s own example is a collection page: wrap the product grid in a partial, and when a customer filters or sorts, only that grid needs to refresh.

That’s a pattern I’ve hand-built before, on the Merch Team storefronts, where custom cart and filtering logic needed to update part of a page without a full reload. Doing that today means writing your own fetch-and-replace JavaScript against a Section Rendering API endpoint and wiring up the DOM swap yourself. A native tag for exactly this removes a chunk of boilerplate that shows up in almost every theme build with any dynamic filtering, sorting, or cart interaction.

Why this is worth the attention

Two things stand out to me beyond the obvious “less boilerplate”:

• Templates become genuinely readable. Right now, understanding a page means reconstructing it in your head from multiple files. Moving that structure into Liquid means the template is the documentation.
• It’s not just for humans. Shopify’s own docs note that a coding agent can read a complete template far more reliably than it can reconstruct one from several linked files. Given how much theme work now involves AI-assisted tooling, that’s not a throwaway line.

Nothing breaks in the meantime

This is a genuinely low-risk one to try. Existing themes, sections, theme settings, and JSON templates are all still fully supported, so this isn’t a “migrate or fall behind” situation. You opt in by selecting Liquid July ‘26 changes under feature previews, or by starting from the skeleton theme release candidate.

It’s still a developer preview, not something I’d put on a live client store yet, but it’s the kind of change worth testing on a low-stakes project early. If you’re maintaining a theme with more than a handful of sections, or you’ve ever hand-rolled a partial-refresh pattern for a filtered collection page, this is worth ten minutes of your time to go read.

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