Software as a Service (SaaS) has seen rapid growth in recent years, thanks to its ability to adapt to diverse user needs through subscription-based models. However, as pricing models enhance the customization of subscriptions, managing the associated constraints within a system's codebase becomes increasingly challenging. In response, Pricing-driven Development and Operation has emerged to integrate pricing considerations across the software lifecycle. Among its most challenging objectives is regulating feature access according to users' subscriptions -- a process that requires managing a multitude of conditions throughout the system's codebase. Feature toggles have traditionally been employed to manage dynamic system behavior, but their application to pricing-driven constraints presents unique challenges. When used to enforce subscription-based restrictions, toggles must adapt -- among other factors -- to individual user's use of features, ensuring that subscription limits are not exceeded. Despite the increasing significance of this problem, current industrial solutions lack explicit support for pricing-driven feature toggling, and existing academic contributions remain constrained to specific architectures. This paper contributes to fill this gap by introducing HORIZON, a classification and comparison framework for feature toggling tools tailored to pricing-driven environments. Its utility is demonstrated by categorizing the solutions identified in the literature as promising for such environments, revealing both their strengths and limitations, and thereby pinpointing critical avenues for improvement. In doing so, HORIZON not only provides a comprehensive view of the current landscape but also lays the groundwork for a focused research agenda, guiding the development of more robust and adaptable solutions for streamlining SaaS development and operations driven by pricings.

翻译：近年来，软件即服务（SaaS）因其通过订阅模式适应多样化用户需求的能力而快速增长。然而，随着定价模式增强订阅的定制化程度，在系统代码库中管理相关约束变得日益困难。为此，定价驱动开发与运维应运而生，旨在将定价考量整合到软件全生命周期中。其中最富挑战性的目标之一是根据用户订阅来调控功能访问——这一过程需要在系统代码库中管理大量条件。传统上，特征切换技术被用于管理系统动态行为，但其在定价驱动约束中的应用面临独特挑战。当用于强制执行基于订阅的限制时，切换机制必须（除其他因素外）适应个体用户对功能的使用情况，确保不超过订阅限制。尽管该问题的重要性日益凸显，当前工业解决方案缺乏对定价驱动特征切换的明确支持，现有学术成果也局限于特定架构。本文通过引入HORIZON来填补这一空白，这是一个专为定价驱动环境定制的特征切换工具分类与比较框架。其效用通过以下方式得到验证：对文献中识别出的、适用于此类环境的有前景解决方案进行分类，揭示其优势与局限，从而指明关键改进方向。通过这一工作，HORIZON不仅提供了当前研究现状的全面视图，还为聚焦的研究议程奠定了基础，指导开发更稳健、适应性更强的解决方案，以简化由定价驱动的SaaS开发与运维流程。