Exploring Flutter + FaaS Integration for Unified Development at Xianyu

Xianyu is building a future development system that unifies front‑end and back‑end using Flutter and Function‑as‑a‑Service (FaaS), aiming to let engineers write business code with a single language and stack.

Flutter’s cross‑platform capability has already been used to standardize the app’s technology stack, and FaaS is introduced to abstract away backend environments, lowering entry barriers and allowing developers to focus on business logic.

The evolution creates a new infrastructure layer for integrated development. Two fundamental questions are raised: what capabilities should the Flutter+FaaS infrastructure provide, and how will business development look on this unified platform?

In the integrated scenario, development concerns are distilled into four areas: data processing (now handled by FaaS functions), network communication (lightweight, function‑call‑like interactions), state management (minimized, moving toward backend‑managed state), and UI rendering (reactive, data‑driven UI enabled by Flutter).

The proposed framework introduces a “Story” (a product feature) divided into virtual “Scene”s. Each Scene consists of three parts: Model (raw data processing, runs in FaaS), Converter (transforms data to UI state, also in FaaS), and Render (draws the UI on the client). Data flows unidirectionally, and events are first handled locally before being routed to the opposite side.

Key challenges include building a robust deployment toolchain, implementing full‑link tracing and monitoring, ensuring reliable network communication in weak‑network scenarios, and devising component decomposition strategies for complex pages.