BRHC: Backend-driven Reactive Hypermedia Controls with a Statically Typed Kotlin DSL

2026-07-31

AI Summary

This work addresses logical redundancy, state fragmentation, and poor maintainability arising from front-end/back-end heterogeneity in AI-generated web applications by proposing a backend-driven hypermedia application model. The approach uniquely integrates Kotlin’s statically typed HTML DSL with a reactive signal mechanism, enabling automatic synchronization between UI and backend state through type-safe custom HTML attributes and builder patterns, thereby substantially reducing reliance on JavaScript. Built upon HtmlFlow extensions, Datastar data attributes, and the Spring MVC architecture, the method demonstrates in the Petclinic case study a near-complete elimination of client-side scripting, enhanced type safety, and the realization of an isomorphic reactive interaction paradigm across frontend and backend.

Abstract

AI-assisted coding tools (e.g., Copilot, Cursor, Claude) are increasingly ubiquitous and enable rapid generation of web applications. However, this raises concerns regarding complexity, longevity and the long-term maintainability of generated systems. A key source of complexity is the heterogeneity between backend and frontend programming models, where multiple languages and paradigms are combined within a single application, often leading to duplicated logic and fragmented state management. To address this issue, recent approaches (e.g., HTMX, Turbo Hotwire, Datastar, etc.) follow the Hypermedia-Driven Application (HDA) model, positioning HTML as the primary communication medium between client and server. Unlike SPA-centric architectures, HDA systems shift the application state and interaction logic to the server, where backend-driven reactive signals synchronize with the client user interface. However, these approaches still introduce complexity through custom attributes and do not fully eliminate JavaScript, particularly in computed expressions. In this work, we propose a statically typed approach using a Kotlin-based HTML DSL (Domain-Specific Language) for backend-driven reactive web applications. We extend the HtmlFlow Kotlin DSL with typed custom HTML attributes (i.e., Datastar data-* attributes) and signal-based bindings using statically typed builders. We demonstrate the approach through a catalog of reactive interaction patterns and a Petclinic Spring MVC case study. The results indicate that the proposed approach can nearly eliminate the need for JavaScript while improving type safety and preserving a homogeneous programming model across frontend and backend, bridged through a backend-driven reactive, signal-centric architecture.

Problem

• hypermedia-driven applications
• frontend-backend heterogeneity
• reactive web applications
• JavaScript elimination
• maintainability

Innovation

• Statically Typed DSL
• Backend-driven Reactive
• Hypermedia Controls
• Signal-based Binding
• Kotlin HTML DSL