Every SaaS platform eventually faces the request for "Excel-like" capabilities, but implementing user-defined logic within a mature application is a full-stack architectural challenge that goes far beyond a simple UI widget. This session dissects the engineering behind Layer’s "FormulaV2," a drag-and-drop logic engine designed to bridge technical complexity and user usability.

We will examine the architectural realities of managing a custom evaluation engine across a large codebase, exploring how to synchronize backend performance with frontend flexibility using tools like Rete.js and Typebox. Attendees will gain insights into managing cross-cutting concerns—from strict type safety and recursive dependencies to API integrations—to build a system that intuitively guides users through complex logic without compromising engineering stability.