Compatio SB3 / Guide.

Enterprise retailers run storefronts on Shopify, Magento, BigCommerce, and Optimizely — each with different APIs, auth models, and cart semantics. Compatio needed a product-configurator widget that embeds into any of them, handles per-client customization without redeploys, and stays fast enough to ship inside someone else's page.

I designed the full request path from embedded widget to backend: a config-driven, container-based UI builder on the front end, an Apollo GraphQL + REST integration layer, and platform middleware that normalizes all four storefront APIs behind one interface. A ServiceWrapper abstraction handles model-spec fetching, price-engine calls, and per-instance session provisioning, while AuthManager manages multi-source token retrieval and platform-specific auth (Optimizely bill-to/ship-to headers, token-expiry re-login flows). A JavaScript middleware system plus admin-panel integration lets each client customize runtime behavior with zero redeploys.

In production for multiple enterprise clients. A multi-phase performance overhaul — React context split into independently-memoized slices, O(n) scans replaced with O(1) Set/Map lookups on hot paths, and sub-50KB entry-point budgets enforced via code-splitting, lazy themes, and Preact substitution — keeps the embedded bundle lean. An end-to-end GA4 pipeline gives clients conversion attribution down to widget and recommender instance.