Ecommerce has changed at its foundation. The monolithic architecture that bundled everything into a single platform has given way to headless ecommerce and, a step further, to composable commerce. If your store is starting to hold you back (slow deploys, fragile integrations, performance that won't recover), that is usually the first sign.
At Kiwop we have delivered more than 80 ecommerce projects with a 92% client retention rate. That experience has taught us when a monolith stops paying off, when headless makes the difference and when it is better not to migrate yet.
What is headless ecommerce?
Headless ecommerce separates the frontend layer (the interface your customer sees) from the backend layer (the business logic and the data). Frontend and backend run independently and talk to each other through APIs.
Unlike the traditional model, where everything is integrated into a single platform, headless lets you connect several interfaces (web, mobile app, kiosks, IoT devices) to a single backend. Each experience is tailored separately and adapts faster to new technologies and to the market.
Headless vs composable commerce: the difference that matters
They get mixed up, but they are not the same, and the distinction decides your architecture.
Headless decouples the frontend from the backend. It is a change in the presentation layer: you can still keep a monolithic backend behind it.
Composable goes further. Each backend component (catalogue, checkout, search, order management) is also independent and interchangeable, chosen as the best available solution (best-of-breed) and connected through APIs. Headless is, in fact, one of the four pillars of the MACH architecture that underpins composable.
In practice the line has blurred: almost every composable project is headless, and many headless projects end up composing their backend piece by piece. That is why this guide covers both.
Advantages of headless ecommerce
- Unlimited user experience: tailored interfaces for every device and channel, without the constraints of an integrated platform.
- Scalability and agility: you scale or modify specific parts without touching the rest of the system.
- Performance: by decoupling the frontend you can optimise loading with SSR/SSG and reduce the bounce rate.
- Advanced personalisation: you adapt the experience to each customer, which raises conversion and loyalty.
- Faster innovation: you integrate new technologies and channels without waiting for the platform to support them.
- Security: separating layers reduces the exposure surface of critical data.
MACH architecture: the four pillars of composable commerce
MACH is not a product, it is a set of principles:
- Microservices: each business function (catalogue, inventory, pricing, orders) is an autonomous service. If one fails or needs to scale, it does not drag the rest down.
- API-first: all communication runs through well documented APIs, so any frontend (web, app, kiosk, IoT) consumes the same data and integrates ERP, CRM or marketing tools without duplicating logic.
- Cloud-native: infrastructure designed for the cloud, with autoscaling and zero-downtime deployments. On a Black Friday the checkout scales while the rest keeps its normal load.
- Headless: the frontend is built with whatever technology you want (Astro, Next.js, Remix, a native app) consuming data through APIs.
Meeting three out of four is not MACH, just as a car without wheels is not a car.
Monolithic vs composable: 7 signs your monolith is holding you back
Not every store needs composable. For a small, stable catalogue, a well configured monolith is still the most efficient option. But there are clear signs you have hit the ceiling:
- The time-to-market for a new feature is over 8 weeks.
- Performance degrades with every extension: LCP above 3 seconds and Core Web Vitals in the red.
- You operate in more than 3 markets with different tax, language and logistics requirements.
- Your team spends more than 40% of its time on maintenance instead of innovation.
- You need to sell on channels your platform does not support natively (marketplaces, social commerce, B2B2C).
- Integrations with your ERP or CRM are fragile and break with every platform update.
- Your total cost of ownership rises every year without a matching increase in value.
If you recognise three or more, it is time to evaluate the transition. Not all at once: gradual migration exists and it works.
Best headless and composable platforms
The ecosystem has matured and it is no longer only enterprise territory. Open-source options have opened composable up to the mid-market too.
- commercetools: the enterprise reference. Native API-first, multi-store and multi-market. Ideal from 50,000 SKUs and several countries; its GMV-based pricing weighs on low volumes.
- Medusa (open-source): a headless framework in Node.js, highly extensible and with no vendor lock-in. Multi-region and multi-currency.
- Saleor (open-source): composable built on Python and GraphQL, with a powerful admin and a developer-friendly approach.
- Shopify Hydrogen: the fast route to headless if you are already on Shopify, with Shopify's backend and a React/Remix frontend. We work on it in Shopify development and break it down in our technical guide to Shopify Hydrogen.
- Adobe Commerce (Magento): supports headless via GraphQL and PWA Studio, powerful for complex catalogues and demanding business logic. Before you make the jump, read when NOT to migrate to Magento headless; we work on it in Magento development.
- BigCommerce: a hybrid approach, SaaS backend with open APIs. A good B2B option (customer-specific price lists, recurring orders).
For the frontend, Next.js is one of the best options for a headless ecommerce. There is no universally best platform: there is the one best suited to your volume, your team and your level of personalisation.
How to migrate: the strangler fig pattern
Migrating from a monolith to composable does not require a big bang. The strangler fig pattern allows a gradual, controlled transition:
- Identify the component with the most friction (usually search, checkout or content management).
- Build the new service in parallel, while the monolith keeps running.
- Redirect traffic progressively (10%, 25%, 50%, 100%) through an API gateway.
- Decommission the monolith component only once the new one has proven stable.
- Repeat with the next component.
In our experience across more than 80 projects, gradual migrations have a much higher success rate than full re-launches. The key is to measure the impact of each phase before moving on.
Performance and SEO of headless commerce
Performance is ranking and it is conversion. The headless architecture impacts both fronts:
- LCP: with SSR/SSG (Astro, Next.js) you serve HTML in under 1 second. Our projects record a +35% performance improvement after migration.
- INP: without the heavy JavaScript of the monolith, interactivity improves.
- CLS: components with defined dimensions, no layout shifts.
- Crawlability: SSR guarantees that Google indexes everything without depending on JavaScript, with clean URLs and structured data free of theme constraints.
If you want to make the most of this route, in composable commerce we analyse your case and design the architecture.
Frequently asked questions
Is composable commerce the same as headless?
No. Headless is one of the four pillars of MACH: it decouples the frontend, but the backend can still be monolithic. Composable goes further, because each backend component is also independent and interchangeable.
How much does it cost to migrate to composable commerce?
It depends on the catalogue, the integrations and the markets. The strangler fig pattern spreads the investment across phases with measurable ROI, and open-source options like Medusa or Saleor reduce licensing costs.
Is it only for large companies?
Not anymore. Open-source platforms have democratised access. A store with 5,000 to 10,000 SKUs and a presence in 2 or 3 markets can benefit without the investment it required five years ago.
What happens to my catalogue during the migration?
With the strangler fig pattern the monolith keeps running normally while the new components are built. There is no downtime and no data loss.
Do I need an in-house technical team?
It is advisable for day-to-day operations, but the implementation and migration can be outsourced to an agency that transfers the knowledge progressively.
Which platform should I choose?
commercetools for high-volume enterprise, Medusa or Saleor if you value open-source and full control, Shopify Hydrogen if you already run on Shopify, and Magento or Adobe Commerce for complex catalogues.
Conclusion
The monolith did its job for a decade, but omnichannel, real-time personalisation and extreme performance demand a different foundation. Headless and composable are not a fad: they are the answer to real problems like deploys that take hours, fragile integrations and platforms that limit instead of enable.
If your ecommerce has reached the point where the business outgrows the platform, let's talk and we will see how to remove those limits.