Digital platforms shape how people communicate, deliberate, and form opinions. Studying these dynamics has become increasingly difficult due to restricted data access, ethical constraints on real-world experiments, and limitations of existing research tools. VIRENA (Virtual Arena) is a platform that enables controlled experimentation in realistic social media environments. Multiple participants interact simultaneously in realistic replicas of feed-based platforms (Instagram, Facebook, Reddit) and messaging apps (WhatsApp, Messenger). Large language model-powered AI agents participate alongside humans with configurable personas and realistic behavior. Researchers can manipulate content moderation approaches, pre-schedule stimulus content, and run experiments across conditions through a visual interface requiring no programming skills. VIRENA makes possible research designs that were previously impractical: studying human--AI interaction in realistic social contexts, experimentally comparing moderation interventions, and observing group deliberation as it unfolds. Built on open-source technologies that ensure data remain under institutional control and comply with data protection requirements, VIRENA is currently in use at the University of Zurich and available for pilot collaborations. Designed for researchers, educators, and public organizations alike, VIRENA's no-code interface makes controlled social media simulation accessible across disciplines and sectors. This paper documents its design, architecture, and capabilities.

翻译：数字平台塑造着人们的沟通、协商与意见形成方式。由于数据访问受限、现实实验的伦理约束以及现有研究工具的局限性，研究这些动态变得日益困难。VIRENA（虚拟竞技场）是一个能够在真实社交媒体环境中进行受控实验的平台。多名参与者可在基于信息流的平台（Instagram、Facebook、Reddit）和即时通讯应用（WhatsApp、Messenger）的高度仿真复刻环境中同时交互。基于大语言模型的智能体以可配置的角色身份和拟真行为与人类共同参与。研究者可通过无需编程技能的可视化界面操控内容审核策略、预设激励内容，并在不同实验条件下运行实验。VIRENA实现了以往难以实施的研究设计：在真实社交情境中研究人机交互、通过实验比较内容干预措施、实时观察群体协商过程。该平台基于开源技术构建，确保数据受机构管控并符合数据保护要求，目前已在苏黎世大学投入使用并开放试点合作。VIRENA的无代码界面专为研究者、教育工作者及公共机构设计，使得跨学科、跨领域的受控社交媒体模拟成为可能。本文详细阐述了其设计理念、架构体系与功能特性。