API-first commerce means the commerce platform is built so that every capability is available through a documented API before it is available anywhere else. Product data, cart state, checkout logic, order management, customer records, inventory levels, promotions, and pricing rules are all exposed as endpoints. Any storefront, mobile app, POS system, or partner integration consumes those APIs. The platform's own admin UI is one consumer among many.
## Why API-first matters
In a non-API-first platform, capabilities are often built for the platform's own frontend or admin first, with APIs added later as an afterthought. Those APIs tend to be incomplete, inconsistent, or slow. Anything the API cannot do has to be done through the UI, which limits how much can be automated or integrated with other systems. Building a custom storefront or a partner integration on such a platform is a fight against the platform.
An API-first platform inverts this. The API is the contract. The admin UI, the storefront, and any partner integration all use the same interface. If a capability exists in the platform, it exists in the API. This makes headless commerce, composable stacks, and non-standard integrations tractable.
## API-first in the MACH acronym
API-first is the A in
MACH. The MACH Alliance uses it as one of its four defining criteria. But API-first predates MACH by many years. commercetools, BigCommerce, and Shopify all promoted API-first as a differentiator long before MACH was coined. It is a design property of the platform, not a vendor certification.
## What API-first is not
Having APIs is not the same as being API-first. Every modern ecommerce platform has some kind of API. What matters is whether the API is complete (every capability is accessible), consistent (the API models are stable and predictable), and treated as the primary interface. A platform where 80% of capabilities are in the API and 20% are only in the admin UI is not API-first, even if the marketing says otherwise.
The way to check is to ask a specific question: can everything a merchant needs to do be done through the API? If the answer includes "except for X, Y, and Z, which need the admin UI," the platform is not truly API-first for merchants who need to automate those things.
## How Frntkey relates
Frntkey is a consumer of API-first commerce platforms.
Norce exposes its full capability through APIs, which is what makes it a suitable backend for a headless frontend.
Shopware exposes its full capability through the Store API. Frntkey talks to those APIs and renders the storefront. When merchants ask whether Frntkey can support a specific commerce feature, the answer usually depends on whether the backend exposes that feature through its API, not on Frntkey itself.
## Related terms
Headless commerce ·
Composable commerce ·
MACH architecture ·
Storefront API