Shopify Online Store 2.0: Architecture, Sections, JSON Templates & When to Migrate

What Online Store 2.0 Actually Is

Online Store 2.0 (OS 2.0) is the name Shopify gave to the 2021 overhaul of its theme architecture. It is not a separate Shopify plan, a new admin or a different storefront product — it is the set of changes that turned themes from mostly-fixed Liquid files into composable, editor-driven, app-extensible documents. Every theme in the Shopify Theme Store is now OS 2.0, and so are all of Shopify's free themes in the Theme Store — including the current flagship, Horizon.

The clearest way to grasp what changed is to look at what came before. Pre-2.0 themes — now called Vintage themes — split in two: sectioned ones could assemble only the homepage through the theme editor, and non-sectioned ones couldn't rearrange even that. Every other template (product page, collection page, blog post, cart) was a fixed Liquid file. Merchants who wanted a different product page had to edit theme code or pay a developer.

OS 2.0 turned each template into a JSON object that lists which sections render, in what order, with which settings — all editable from the admin, with no code.

That sentence is more important than it looks. It frames the migration question correctly: OS 2.0 is not a forced upgrade, but new features are shipping to OS 2.0 first and the long-term direction of the platform is clear. If you are evaluating a re-platforming budget, the right question is when, not whether.

The rest of this guide gives you the architecture, the trade-offs, the migration plan and the cost paths so you can make that call.

If you inherited the store and cannot tell which generation you are on — or what a previous developer left inside the theme — start one step earlier. Our Shopify store code audit guide walks the free checks that reveal the theme generation, leftover app code and legacy checkout dependencies before you commit to a migration budget.

If you are coming in cold and want a more general theme primer first, the Shopify theme guide explains how themes, templates and the editor work end-to-end. If you are evaluating Liquid as a language, the Liquid explainer goes deeper on syntax. This article focuses specifically on the OS 2.0 architecture itself.

The Four Primitives That Run OS 2.0

OS 2.0 is best understood not as a feature list but as four primitives that compose into everything else. Each one solves a specific problem with how Vintage themes worked, and together they redefine what is editable, what is reusable and where customisation lives.

A fifth piece — section groups — extends the first primitive to the header and footer. Section groups let merchants add sections (announcement bars, secondary nav, promo strips) into the header or footer area through the same editor surface, instead of editing layout files. Combined with the four primitives above, very little of the storefront stays hard-coded — with one named exception: the gift card page can't be a JSON template at all, so it has no sections to arrange in the editor.

Metafields & Dynamic Sources: The No-Code Data Layer

Before OS 2.0, anything beyond Shopify's built-in product fields — spec tables, ingredients, country of origin, downloadable manuals, size guides, custom badges — was a Liquid edit. Developers added a snippet, hard-coded the layout, and any future change went back through the same developer. Multiply that by a few hundred products and the maintenance cost was real.

Metafields moved the custom-data definition into the admin. Dynamic sources made those metafields bindable directly inside the theme editor — a section setting that previously held a literal string can now point to a metafield. The merchant fills the field on each product; the storefront renders. The Liquid snippet disappears.

Zoom

Practically, this changes who owns three jobs across the content lifecycle:

This separation is the OS 2.0 win that delivers the most ongoing value, because content entry is the job done every week. The other primitives matter at re-platforming time; metafields plus dynamic sources matter every day.

OS 2.0 vs Vintage Themes: What Changes Day-to-Day

Feature lists undersell the difference. The right comparison is operational: for the changes you actually make every month, which architecture forces you back into code?

Across every row, the pattern is the same: tasks that needed a developer in Vintage now belong to the merchant in OS 2.0. That is the actual product story — not new visuals, but a shorter loop between "we want to change this" and the change shipping.

Navigation is one concrete case: Shopify says every OS 2.0 theme supports multilevel menus, while older sectioned themes might need updating, so whether a shopper sees your third menu level depends on which generation you are on. Whether that depth also costs you search traffic is a separate question.

What OS 2.0 Still Does Not Do

It is more useful to know where OS 2.0 stops than to memorise what it covers. Four limits matter in practice — each one is a real constraint that has bitten merchants mid-migration. A fifth is a set of hard platform caps that Shopify publishes as numbers.

If checkout customisation is on the roadmap, the rules live in a separate Shopify framework — see checkout UI extensions for which checkout steps apps can change and which require Plus, and the broader checkout extensibility docs for the full plan boundary. Neither lives inside the OS 2.0 theme editor.

How to Tell If You're Already on OS 2.0

Before scoping any migration, confirm what you're actually on. Many merchants assume they're on Vintage because their theme looks dated — but a theme bought in 2019 from the Theme Store may have been kept up-to-date by its vendor and is now an OS 2.0 build. The architecture is independent of the visual design.

Run these three checks in your Shopify admin. If all three pass, you're on OS 2.0. If any fail, you're on a Vintage theme — or on an OS 2.0 theme that hasn't been updated to the latest features.

1. The product-page editor test. Open Online Store → Themes → Customize and switch the editor preview from the homepage to a product template. If you can add, remove and reorder sections on the product page, you're on OS 2.0. If the page is a fixed layout with only a few hard-coded settings, you're on Vintage.
2. The app block test. In the same editor, open any section and click Add block. If an Apps group appears in the block picker, that section supports app blocks — an OS 2.0 signal; app embeds alone prove nothing, because vintage themes support them too. The group shows only when you have a compatible app installed.
3. The metafield binding test. Open any section setting in the editor that accepts text. If a small database icon appears next to the input and lets you "connect to dynamic source", the theme supports dynamic sources — another OS 2.0 signal.

The outcome of this 30-second audit changes the next steps entirely. If you're on OS 2.0, the action is to update to the latest theme version, evaluate whether to move to Horizon (covered next), and audit unused sections. If you're on Vintage, the action is the migration project covered further below.

Horizon vs Dawn: The 2025 Flagship Shift

For four years, Dawn was the answer to "which theme should I start with?" In 2025 Shopify shipped Horizon as the new flagship, built on theme blocks. Both themes are OS 2.0 to the core, so beyond Horizon's theme blocks the choice is about which editor surface and which design language fits the brand.

Horizon is the right default for stores launching now, with the caveat that any team with a long Dawn-based development history will move faster by sticking with what they know. The migration from Dawn to Horizon is real work — it is closer to a redesign than a version bump.

Migration: When to Move and What Breaks

The biggest single mistake teams make is treating a Vintage-to-OS-2.0 move as a theme swap. It isn't. It is a re-platforming exercise inside Shopify, scoped by how much the current theme has been customised. A theme with stock Vintage Liquid migrates quickly; a theme with two years of bespoke snippets, custom JSON-LD blocks, and theme-edited app integrations is a real project.

Five phases keep that project under control. Do them in order — skipping the audit is what creates the all-night cutover horror stories.

For broader migration scenarios that involve moving to Shopify from another platform entirely (WooCommerce, Magento, BigCommerce), the platform migration guide covers SEO, data, and cutover patterns that apply on top of an OS 2.0 build.

Cost & Effort: Four Realistic Paths

The cost of an OS 2.0 build is mostly determined by how much custom work the current site carries, not by OS 2.0 itself. The architecture is the same across all four paths below; what changes is who does the work and how bespoke the result is. The time and cost ranges in the table are our working estimates, not Shopify figures — except the premium theme price, which reflects paid themes listed in the Theme Store.

Two patterns hold across all four paths. First, the DIY ceiling is higher than people expect on OS 2.0 — sections everywhere plus metafields covers most merchant requests without any code. Second, the developer ceiling is also higher — bespoke sections built once become reusable, drag-and-droppable assets for the merchant team forever. Both ends of the spectrum get better economics from OS 2.0 than from Vintage.

Side budget items to factor in regardless of path: a paid metafield manager app if the catalogue is large, premium sections if the chosen theme is sparse, and a performance audit if the storefront ends up with more than a handful of third-party app blocks. If the build will include a developer, the Shopify developer hiring guide covers what to vet for; custom design choices covers the design side.

OS 2.0 with Markets, B2B & Headless

OS 2.0 is rarely the only Shopify surface a growth-stage merchant uses. Three platform capabilities show up in almost every re-platforming conversation. The table below summarises how each one fits with OS 2.0; the notes after expand the nuance.

The pattern across all three is the same: OS 2.0 handles the storefront, and the bigger Shopify capabilities sit cleanly on top of it. On free Shopify themes from version 11.0.0, the quick order list and volume pricing need no code; on older versions Shopify's help says to update the theme or add code.

Of these three, Hydrogen is the one that replaces the OS 2.0 theme, and the gap between the two is narrower in 2026 than it was in 2021. If you're scoping a re-platforming project, default to OS 2.0 and let the headless decision be a separate, evidence-driven conversation.

The Bottom Line

OS 2.0 is no longer the new thing — it is the baseline. The decision in front of most merchants is not "should I use OS 2.0?" but "am I still on a Vintage theme, and if so, what is the cost of moving versus the cost of staying?" That answer is rarely emotional; it comes from the diagnostic in section 6 and the cost table in section 9.

Frequently Asked Questions