Supported Platforms
This page sets expectations before you sign up — your platform category, what’s universal across categories, and what your category typically provides during onboarding. Firmly maintains adapters for a wide range of commerce platforms and speaks each merchant’s native API, so most stores connect without a custom build.
Standard vs Advanced — which is my store?
Most stores are Standard. The Standard checkout — cart, address, one shipment, order — works on every connected platform with no extra setup.
You need Advanced only if your products or fulfillment call for it: items that split into multiple shipments (furniture, appliances, large or multi-warehouse orders), delivery scheduling or pickup, add-ons and protection plans, or ZIP-coverage gating before checkout. Advanced also requires your commerce platform to support those richer operations.
Not sure? Assume Standard. If your catalog or fulfillment turns out to need Advanced, Firmly flags it during onboarding and confirms whether your platform can support it — you don’t have to decide up front.
What category is your store in?
Answer the questions in order — the first one that matches is your category. Click your category to jump to what you provide for it.
| Question | If yes, your category is |
|---|---|
| Did your team build the storefront platform yourselves (in-house, bespoke)? | Custom or in-house |
| Is your storefront composable or API-first (separate microservices for cart, checkout, catalog)? | Composable / API-first |
| Is your storefront headless or heavily customized (decoupled front-end + back-end, custom checkout flow)? | Headless or heavily customized |
| Is your storefront on a major SaaS or enterprise commerce platform (out-of-the-box, light customization)? | Cloud-native |
If you’re uncertain — for example, between headless and composable — just sign up. The wizard or Firmly’s onboarding team will clarify. The distinction usually matters only on Firmly’s side.
What’s true for every category
Regardless of category, Firmly provides the same capabilities — all driven by your platform’s live data:
- Catalog read — products, variants, pricing, and inventory pulled live from your platform. The same pricing and inventory your storefront shows — validated live at transaction time, so there’s no stale data at order placement. (Firmly does keep a catalog index for fast discovery; it’s always confirmed against your live platform before an order is placed — see Catalog & Pricing.)
- Cart orchestration — Firmly handles cart state for the transaction; you don’t manage a separate cart system on top of your existing platform. Line items, addons, promo codes, and shipping methods all flow through your platform’s standard APIs.
- Tax and shipping calculation — using your platform’s live rules.
- Payment tokenization — card, PayPal, Click to Pay, Google Pay, Klarna.
- Order placement — orders land in your native order management system as if a customer placed them directly.
- Affiliate attribution — origin attribution flows back to the destination.
Your existing PSP, OMS, analytics, reporting, and storefront pages stay untouched. Firmly’s scope ends at order placement.
What you provide, by category
What you provide depends on your category — usually just one or two things, captured during the Onboarding Wizard.
Custom or in-house
If your team built the storefront platform yourselves.
What you provide: Endpoint URLs, authentication scheme, example responses.
Composable / API-first
If your storefront is composable or API-first — separate microservices for cart, checkout, catalog.
What you provide: Project key + minimum scope details (if Firmly’s discovery can’t determine them).
Headless or heavily customized
If your storefront is headless or heavily customized — decoupled front-end and back-end, custom checkout flow.
What you provide: Storefront API key + deployment-specific details.
Cloud-native
If your storefront is on a major SaaS or enterprise commerce platform, out-of-the-box with light customization.
What you provide: Just the store URL. Firmly handles the rest.
For cloud-native, the specifics are confirmed inside the wizard during onboarding. For headless, composable, and custom platforms, the credential handover happens in a short conversation with Firmly’s onboarding team alongside the wizard.
Custom platforms — the one exception
The categories above cover merchants whose platform exposes a standard storefront API, including most headless and heavily customized deployments (which provide a storefront API key rather than a custom build). The exception is a truly custom or legacy stack with no standard API surface Firmly’s pre-built adapters can use: for those, Firmly builds a per-merchant adapter. Typical effort is 2–4 weeks, scoped during onboarding.
For these merchants only, it makes sense to contact Firmly before signing up so the adapter scoping conversation can start in parallel with onboarding. For every other category, just sign up.
A Custom Adapter Editor in your Firmly Connect dashboard lets you review, edit, test, and publish the adapter without leaving the portal — see Credentials & API Access → Custom adapter merchants for how it works.
Ready to start?
Sign up at merchant.firmly.ai and walk through the 7-step wizard. See Merchant Quickstart for the abbreviated path.