- No platform wins outright. More checkout control always comes with more maintenance, and the best default conversion comes with the least room to change anything.
- Three things actually differ: how much you can change, what that change costs you later, and what you pay to use your own payment processor.
- Express wallets, one-page layouts and guest checkout are supported everywhere. They will not separate platforms in 2026.
- Do not choose a platform on agentic checkout. The protocols are months old and the public record contradicts itself.
- Replatforming for checkout is almost never the answer. Most of the available gain is configuration and content, on the platform you already have.
None of them, outright. The platforms that give you the most control over checkout also hand you the most maintenance, and the ones with the best out-of-the-box conversion give you the least room to change anything. That trade is the whole story, and where you should sit on it depends on how unusual your order flow is, not on which platform markets its checkout best.
The more useful question is the one buyers rarely ask directly: is my platform actually the thing limiting my checkout? For most stores it isn't. This guide covers what genuinely differs between the major platforms in 2026, which situation each one fits, and how to tell whether your checkout problem is a platform problem or something you can fix where you are.
The three things that actually differ
Feature checklists obscure more than they reveal here. Three axes explain almost every real difference.
How much you can change. At one end, Shopify gives you a sandboxed extension framework with defined insertion points. At the other, BigCommerce publishes its entire checkout as open source and lets you fork it. Adobe Commerce and WooCommerce give you the code because you host it.
What that change costs you later. This is the axis nobody weighs properly at decision time. Sandboxed customisations survive platform upgrades. Forked checkouts don't: you own that fork forever, including every security patch and every payment integration that assumed the stock flow.
What you pay to use your own processor. Platform fees for going outside the preferred payment ecosystem are a real, recurring cost that scales with revenue, and they vary enough between platforms to outweigh licence fees at volume.
Everything below is a position on those three axes.
Shopify and Shopify Plus
Control: structured and sandboxed. Since the deprecation of checkout.liquid (unsupported for the Information, Shipping and Payment steps from August 13, 2024, and sunset for the Thank you and Order status pages from August 28, 2025), customisation happens through Checkout UI extensions, Shopify Functions, the Branding API and Web Pixels. Extensions render at defined targets using Shopify's own components, in a sandbox that cannot load external scripts.
The plan boundary is widely misunderstood in both directions. Standard plans are not locked out: apps from the Shopify App Store can use Functions for discounts, delivery and payment customisations, and UI extensions can render on the Thank you and Order status pages. What Plus adds is the part most checkout projects actually want: UI extensions inside the Information, Shipping and Payment steps, custom apps built on Functions, and the full Branding API. Plus is commonly cited at around $2,300/month, though Shopify doesn't publish a fixed public price.
What it costs you later: very little, and this is Shopify's real argument. Sandboxed extensions survive upgrades and don't touch your PCI scope. The migration away from checkout.liquid was painful precisely because it converted unbounded customisation into bounded customisation, but the stores that completed it stopped breaking on every platform update.
Watch for: if your last serious checkout customisation predates 2024, assume something is broken right now. The recurring damage we see is analytics: tracking that lived in additional scripts didn't survive, and nobody noticed because revenue kept arriving. If that sounds familiar, check that your checkout funnel events still fire. Shopify Scripts has also been retired in favour of Functions, and published sources disagree on the exact final date, so check Settings → Checkout in your admin rather than trusting a blog. Non-Plus stores had a separate Thank you and Order status deadline reported as August 26, 2026, which has now passed.
Payment economics: no platform fee on Shopify Payments; an additional fee for third-party processors, from 2% on Basic down to 0.2% on Plus. The best pricing is tied to staying inside the ecosystem.
Best for: stores whose order flow is fairly standard, who want the strongest default conversion and the lowest maintenance burden, and who can live inside defined extension points. More on how we work here: Shopify checkout optimization.
BigCommerce
Control: the most of any hosted platform, by a distance. The checkout front end, checkout-js, is published on GitHub. You can fork it, add steps, add fields, restructure the flow, and host your own build, on every plan rather than only at enterprise tier. There's also a Checkout SDK for building against the same APIs without forking, and full REST and GraphQL access underneath.
What it costs you later: you own the fork. Permanently. Every upstream security fix, every new payment method, every browser change is now partly your problem. This is a genuine engineering commitment, not a weekend project, and it's the single most underestimated cost in platform selection.
Payment economics: BigCommerce's historic pitch was no platform fees on any processor. That changed on June 1, 2026, alongside a plan rename to Core, Growth and above: roughly 20 embedded providers remain fee-free, while non-embedded providers now carry a tiered Open Payment Provider fee. If processor freedom was your reason for choosing BigCommerce, re-run that arithmetic.
Watch for: one agency analysis reports BigCommerce live store counts down around 8% year over year in early 2026, against a Shopify estate commonly cited near 4.8 million stores and roughly 30% US market share. Both figures are single-source and directional, but platform momentum is a legitimate input to a decision you'll live with for years, and worth verifying independently rather than taking from us or from anyone selling you a migration.
Best for: stores with genuinely unusual checkout requirements and the in-house or agency engineering capacity to maintain a fork, particularly in B2B. See also BigCommerce checkout optimization.
Adobe Commerce and Magento Open Source
Control: total, because you host it. Also the hardest to exercise. The default checkout is a Knockout.js application whose structure is built from XML into a deeply nested PHP array, serialised to JSON, and rendered client-side. Customising it usually means mutating that array by string path, and when the path is wrong, nothing happens and nothing is logged. We've written a full breakdown of why this is so painful.
The most telling detail is Adobe's own: for Edge Delivery Services storefronts, Adobe ships Luma Bridge, a documented mechanism that lets a new storefront hand the shopper back to the existing PHP checkout instead of rebuilding it. Adobe's next-generation architecture includes an official escape hatch for avoiding a checkout rebuild.
What it costs you later: the highest maintenance burden here, and the largest permutation space for bugs. Every extension plugs into the same object.
Payment economics: no platform fee. Any processor, any terms. For high-volume merchants this alone can justify the hosting and engineering cost.
Best for: complex catalogues, ERP-driven operations, B2B with real pricing hierarchies, multi-market compliance requirements, and anyone whose order flow genuinely can't be expressed in a SaaS platform's model. Overkill for anyone else, and the checkout will cost you more to change than on any other platform here. See Magento checkout optimization and Adobe Commerce checkout optimization.
WooCommerce
Control: complete, and cheap to start. It's PHP running on your own server with hooks and filters everywhere. The block-based checkout has largely replaced the shortcode version, which is faster but has broken a long tail of older extensions that assumed the old markup.
What it costs you later: the plugin stack is the risk, not the platform. A checkout assembled from six plugins from five vendors has no owner when it breaks after a WordPress core update. Hosting, caching and performance are also entirely yours.
Best for: content-led stores, smaller catalogues, teams already fluent in WordPress, and anyone who needs a specific customisation more than they need reliability guarantees. See WooCommerce checkout optimization.
Salesforce Commerce Cloud
Rarely the right answer if you aren't already deep in the Salesforce ecosystem, and usually the right answer if you are. Commerce Cloud's value over Adobe Commerce or commercetools narrows sharply outside that context; it's typically the most expensive option and carries the strongest lock-in. But when Service Cloud, Marketing Cloud and Data Cloud are already in production, the integration gravity generally outweighs the premium. Checkout is customisable through the Composable Storefront and PWA Kit, with implementation-partner economics attached.
Shopware
Worth knowing about if you're European mid-market or B2B, and routinely missing from comparisons written for US audiences. Modern PHP stack, headless-capable through its API, and a credible B2B suite covering price lists, customer-specific catalogues and quote workflows. Smaller ecosystem than Adobe Commerce; stronger regional partner network in Germany and adjacent markets.
commercetools and composable
Not a checkout, by design. You get APIs and assemble the flow yourself, optionally using commercetools Checkout for a pre-built UI. Maximum control, maximum responsibility, and the checkout becomes a product your team owns and staffs indefinitely.
Composable is a legitimate answer for multi-brand, multi-region, content-heavy operations. It is very rarely the answer to "our checkout converts badly." If a composable rebuild is being proposed as a conversion fix, ask what specifically about the current checkout can't be changed where it is. The answer is usually "nothing, but the rebuild was already planned."
Wix, Squarespace and other website builders
Checkout is essentially fixed. Branding, some field control, and the payment methods the platform supports. That's not a criticism: for a store selling a few dozen SKUs, a constrained checkout that works is worth more than a flexible one that needs maintaining. The limit only becomes a problem when your order flow stops being standard, and at that point you've outgrown the platform generally, not just its checkout.
Comparison table
The same three axes, side by side. Scroll sideways on a phone.
| Platform | Control | Maintenance | Own-processor fee | Upgrade-safe | Best fit |
|---|---|---|---|---|---|
| Shopify / Plus | Sandboxed extensions | Low | 0.2% to 2% by plan | Yes | Standard flows, low ops overhead |
| BigCommerce | Open-source fork or SDK | High if forked | Tiered since June 2026 | No, if forked | Unusual flows, has engineers |
| Adobe Commerce | Total, hard to exercise | Highest | None | Partly | Complex catalogue, ERP, B2B |
| WooCommerce | Total via hooks | Medium to high | None | Depends on plugins | Content-led, WordPress teams |
| Salesforce CC | Via Composable Storefront | High | Varies | Partly | Salesforce-native enterprises |
| Shopware | High | Medium to high | None | Partly | EU mid-market and B2B |
| commercetools | You build it | You own it | None | n/a | Multi-brand, multi-region |
| Wix / Squarespace | Minimal | None | Limited choice | Yes | Small catalogues |
Express checkout and one-page: which platforms support what?
This is where the honest answer is dull, and the dullness is the point.
Every serious platform supports express wallets. Apple Pay, Google Pay and PayPal are available across all of the above through standard gateway integrations. Shop Pay is Shopify-exclusive and free with Shopify Payments; Link comes with Stripe wherever Stripe is your processor; Amazon Pay and Fastlane by PayPal work broadly.
One-page checkout is now closer to a default than a differentiator. Shopify's checkout is a single page with collapsing sections. Magento's default is a two-step accordion on one URL. BigCommerce ships an optimised one-page checkout. The layout question has largely been settled by the platforms, which is convenient, because the research on page count is far less decisive than vendors claim.
Guest checkout is supported everywhere and configured badly almost everywhere. No platform forces account creation. Plenty of stores enable it anyway, or bury the guest option where nobody finds it, which tests as equivalent to not offering it.
So if you're choosing a platform on express-checkout or one-page support, that criterion won't separate them. What will separate them is how much of the rest of the flow you need to change.
Agentic checkout: what's actually happening
Worth a short, sceptical section, because it's the newest thing anyone will pitch you and the public record is a mess.
The direction is real. OpenAI and Stripe released the Agentic Commerce Protocol in September 2025 and launched Instant Checkout in ChatGPT, starting with Etsy sellers and announcing Shopify merchants. Google announced the Universal Commerce Protocol at NRF in January 2026, co-developed with Shopify, Etsy, Wayfair and Target, and added cart, catalogue and identity-linking capabilities through early 2026. Microsoft, Perplexity and Amazon all have their own versions.
The detail is contested, and sharply. One account from April 2026 reports that OpenAI pulled native Instant Checkout on March 4, 2026, that only around a dozen Shopify merchants had ever fully integrated it, that the 4% merchant fee introduced in January was suspended, and that OpenAI pivoted to an app-based model. Another account from August 2026 describes over a million Shopify merchants as live. A third says agentic checkout has since moved to Google's protocol and Perplexity's. These cannot all be true, and we can't tell you which is.
Our read: do not choose a platform on agentic-commerce readiness in 2026. The protocols are months old, at least one has already been withdrawn and relaunched in a different form, and the platforms are racing to support all of them. What does transfer regardless of how it settles is unglamorous: clean structured product data, accurate feeds, a checkout that works over an API. Build that and you're ready for whichever standard survives.
Should you replatform for checkout?
Almost never. This is the section that matters most and the one you'll rarely get straight from a firm that builds sites.
Replatforming is one of the most expensive, highest-risk projects an ecommerce business undertakes. It consumes engineering capacity for months, carries real SEO and data-migration risk, and reliably produces a post-launch dip. Checkout, meanwhile, is usually the part of your store that's least constrained by the platform, because almost every platform now permits field reduction, guest checkout, express wallets and early cost transparency, which is where most of the available gain sits.
Before anyone scopes a migration, three questions:
1. Have you exhausted what your current platform allows? Field count, forced account creation, shipping cost visibility, express wallets, error handling, checkout page speed. In most audits we run, the biggest wins are configuration and content, not architecture, and they're available on the platform the store is already on.
2. Can you name the specific thing the platform prevents? Not "the checkout is inflexible" but "we need a purchase-order approval step with three roles and the platform's data model has no concept of it." If nobody can produce that sentence, the constraint probably isn't the platform.
3. Is checkout the actual reason, or the justification? Replatforms are often decided for other reasons (a contract ending, a leadership change, a stack consolidation), and checkout gets recruited as the business case because it's easy to attach revenue to. That's a fine decision; it just deserves an honest one, and the checkout argument shouldn't be doing work it can't support.
Replatforming is right when the constraint is structural and named: a data model that can't express your pricing or account hierarchy, compliance requirements the platform can't meet, a platform you're being forced off, or economics that no longer work at your volume. Those are real. "Our checkout converts badly" is not, on its own, one of them.
If you are already in that conversation, our guide to deciding whether to migrate or modernize covers the one-sentence test, the five cases where migrating is clearly right, and what each path really costs.
Find out whether your platform is really the problem
The honest version of this answer needs three things no article can see: your funnel data, your actual field count and flow, and what your platform genuinely prevents versus what nobody has got round to changing.
Want to start yourself? The checkout audit checklist is the 77 checks we run, published in full. Most of them apply on every platform in this article, which is rather the point. If you are weighing outside help, our guide to who to hire for checkout optimization compares the options, including when the answer is nobody.
Sources
This page dates faster than anything else on our blog. Figures above are attributed in the text; where sources disagree, the article says so rather than picking one. Market-share and store-count figures come from single agency analyses and are directional only.
- Shopify: Checkout extensibility and
checkout.liquiddeprecation - BigCommerce: Open Checkout and Checkout SDK documentation
- Adobe Commerce: Luma Bridge (Edge Delivery Services storefront)
- OpenAI: Instant Checkout and the Agentic Commerce Protocol
- Stripe: Agentic Commerce Protocol announcement
Checkout Experts optimises checkouts on Shopify, BigCommerce, Magento, Adobe Commerce, WooCommerce and custom builds, so we have a view on every platform here and a reason to be fair to all of them. Platform terms, fees and deadlines change often: this page was last reviewed September 24, 2026 and is re-verified every quarter.
