Shopify Checkout Components Explained: What Merchants Need to Know in 2026

The short version: Checkout Components — Shopify's Checkout UI Extensions — are the modern, supported way to customize your checkout. They're sandboxed, React-style components that drop banners, custom fields, and upsells into defined checkout slots, without ever touching checkout.liquid. Here's what they are, what you can build, and what your plan unlocks.

We build Shopify checkout extensions and Functions, so here's the practical explainer.

Why this exists: checkout.liquid is gone

For years, deep checkout customization meant editing checkout.liquid — hand-written code injected into the checkout page. It was powerful but fragile: it broke on platform updates, was hard to keep PCI-safe, and Shopify has now sunset it (alongside Scripts) as of June 30, 2026. (If you're still on it, see our Scripts-to-Functions migration guide.)

Checkout Extensibility is the replacement — and Checkout Components are the most visible part of it.

What "Checkout Components" actually are

Checkout Components are React-style UI components that render in specific, Shopify-defined slots of the hosted checkout — think informational banners, custom input fields, content blocks, and upsell modules. Formally they're Checkout UI Extensions, and they're the frontend layer of the broader Checkout Extensibility framework.

Instead of writing free-form code into the checkout page, you build a component and Shopify renders it, in a supported slot, through its own engine.

The three surfaces of Checkout Extensibility

Checkout Components don't work alone. Extensibility gives you three tools, and most real customizations use a combination:

Components handle what the customer sees; Functions handle the logic; the Branding API handles how it looks. (For when a Function is the right tool vs. a full app, see Shopify Functions vs Apps.)

What you can actually build

The practical, revenue-relevant things merchants add with Checkout Components:

• Trust & info banners — shipping cutoffs, guarantees, delivery promises.
• Custom fields — gift messages, delivery instructions, PO numbers, VAT IDs.
• Upsells & cross-sells — in-checkout offers and add-ons.
• Loyalty & rewards — points balances, redemption prompts.
• Custom delivery & payment logic — via Functions (hide/reorder/rename methods, conditional rules).
• Thank-you / order-status content — order tracking, surveys, and post-purchase upsells after the order is placed.

Why the new model is genuinely better

This is the part that matters most to merchants, even non-technical ones:

• It's secure by design. Extensions run in an isolated sandbox — separate from the checkout page and from each other — with no access to sensitive payment information or the checkout page itself. Custom code can't compromise customer data the way checkout.liquid could.
• It's upgrade-proof. Because Shopify renders your component through its own engine, your customization survives platform upgrades instead of silently breaking after an update.
• It's faster and cleaner. Sandboxed, component-based extensions avoid the performance and maintenance drag of injected checkout code — and keep you aligned with the Built for Shopify performance bar.

In short: you get customization power without the fragility and PCI risk of the old approach.

What's available on your plan

Good news for smaller stores — you're not locked out:

• All Shopify plans support Checkout UI Extensions for block-based customization (banners, fields, content, upsell blocks).
• Shopify Plus is still required for post-purchase extensions, advanced checkout branding, and certain payment customization features.

So basic checkout components are open to everyone; the deepest branding and post-purchase capabilities are a Plus upgrade. (For where the Plus line sits overall, see Shopify Plus vs Shopify.)

How merchants actually get them

Two paths, depending on how custom your need is:

1. Install an app — most common checkout needs (upsells, custom fields, trust badges, loyalty) are covered by App Store apps built on Checkout UI Extensions. No code, fast to deploy.
2. Build a custom extension — for bespoke UI or logic an app can't do, a developer builds a custom Checkout UI Extension (plus Functions for custom rules). Same supported framework, tailored to you.

Either way, you're on Shopify's supported, upgrade-safe foundation — not brittle checkout hacks.

If you're still on checkout.liquid

Then this is your migration path, and the clock has run out: checkout.liquid stopped executing on June 30, 2026. Any checkout customization you relied on there needs rebuilding as Checkout UI Extensions, Functions, and Branding API — the exact move covered in our Scripts-to-Functions migration guide.

We build and migrate Shopify checkout experiences end to end — custom Checkout UI Extensions, Functions, and branding, plus the migration off checkout.liquid. See our Shopify app development and Shopify store development work, or talk to us about your checkout.