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Alternatives · Commerce

Checkout UI Extensions alternatives (2026)

Checkout UI Extensions: The only way to customize checkout—work within the limits.

Its Catch: The sandboxed environment limits what is possible.

Below: 8 free or free-tier tools from the same category (commerce tools), free and open source first, then the closest match by shared tags. Each keeps its own Catch.

  1. 1.MedusaMIT commerce OS you self-host; Cloud from $29/mo

    Free / OSS · OSS/MIT · 36.8k GitHub stars

    VerdictMIT commerce OS. Self-host is free; Cloud starts at $29/mo.

    CatchCommerce OS, not invoices and not card rails. Cloud From $29/mo is not a $0 hobby hatch — self-host is the free path. Distinct from Polar/Hyperswitch (payments) and from Lago (metering).

  2. 2.Spree CommerceBSD-3-Clause Ruby commerce OS; Free Sandbox, no platform fees

    Free / OSS · Freemium · 15.8k GitHub stars

    VerdictBSD-3 Ruby commerce. Self-host free; Sandbox has no CC. Not Medusa.

    CatchRuby commerce + REST/OpenAPI + Next.js storefront — not Medusa MIT Node OS. Solidus (BSD sibling) omitted: same Spree-fork slot. Distinct from Medusa.

  3. 3.SyliusMIT Symfony commerce; Plus is the commercial add-on

    Free / OSS · Freemium · 8.6k GitHub stars

    VerdictMIT PHP commerce on Symfony. Self-host is free; Plus is paid.

    CatchSymfony + API Platform PHP headless — not Medusa MIT Node OS and not JS. Distinct from Medusa and Spree. Plus is commercial, priced on request.

  4. 4.BagistoMIT Laravel/Vue commerce with marketplace and B2B

    Free / OSS · OSS/MIT · 28.3k GitHub stars

    VerdictMIT Laravel commerce. Self-host free. Not Medusa Node.

    CatchLaravel/Vue commerce + marketplace/B2B — PHP twin to Medusa, not Medusa MIT Node OS. Sylius and Spree already cover Symfony/Ruby in Wave 5. Distinct from Medusa.

  5. 5.PrestaShopOSL-3.0 classic PHP cart; pitch the core, not the module store

    Free / OSS · OSS/MIT · 9.2k GitHub stars

    VerdictOSL-3.0 PHP cart. Core is free; ignore the module upsell in the installer.

    Catchinstaller may bundle optional SA commercial modules — pitch core only. Classic PHP cart, not headless Node (Medusa) and not Magento. Distinct from Medusa, Bagisto, Sylius, Spree.

  6. 6.HydrogenShopify React framework for headless commerce

    Free / OSS · OSS/MIT · 2.1k GitHub stars

    VerdictThe official path for Shopify headless—for better and worse.

    CatchYou are locked into Shopify architectural choices. Customization beyond their patterns requires deeper knowledge. Oxygen hosting limits deployment options.

  7. 7.RemixFull stack React that Shopify acquired

    Free / OSS · OSS/MIT · 33.4k GitHub stars

    VerdictWeb fundamentals meet React, now with Shopify backing.

    CatchThe mental model shift from SPA patterns takes adjustment. Some React patterns do not translate directly. The ecosystem is smaller than Next.js.

  8. 8.Shopify CLIThe development tool every Shopify dev needs

    Free / OSS · OSS/MIT · 757 GitHub stars

    VerdictNot optional—just install it and move on.

    CatchOccasional bugs with authentication flows. Resource usage can be heavy. Some advanced workflows still require manual setup.

FAQ

What are the best free alternatives to Checkout UI Extensions?
Medusa, Spree Commerce, Sylius, Bagisto, PrestaShop. All are reviewed on Stack Gems in the same category (commerce tools); 8 free or open source.
What is the catch with Checkout UI Extensions?
The sandboxed environment limits what is possible.
Is there an open-source alternative to Checkout UI Extensions?
Yes: Medusa (OSS/MIT), Spree Commerce (Freemium), Sylius (Freemium), Bagisto (OSS/MIT).

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