From Reactive to Predictive:
Building Thinking UIs with Streaming
Traditional UIs are reactive: the user clicks, the system responds. But modern interfaces , inspired by AI assistants, are evolving into “thinking UIs” that reveal their reasoning step by step, creating more transparent and engaging experiences.
In this talk, we’ll show how to build streaming interfaces with Server-Sent Events and React concurrent features like useTransition and useReducer. We’ll demonstrate a live example that progressively surfaces each step in real time, replacing the loading spinner with a richer, more trustworthy experience.
We’ll also explore how to design interruptible and cancelable streams and apply UX patterns for step-by-step transparency. The architecture works whether you’re simulating responses, calling AI APIs, or running local models, the frontend patterns remain consistent.
By the end, attendees will leave with practical techniques for building interfaces that feel intelligent, responsive, and alive.
Evangelia Mitsopoulou
Founder & CTO & CEO @ Philomath Academy | Mentoring Frontend Engineers | ex-Elastic · ETH Zurich · Google (contract) | React Summit Speaker
About the speaker
With two decades of experience in tech companies, research institutions, and startups, I am dedicated to helping frontend engineers thrive in an ever-evolving landscape. As the founder of Philomath, a frontend engineering academy, I provide high-quality, framework-agnostic training that addresses current industry needs and prepares engineers for future growth.
Before founding Philomath, I spent many years as a frontend engineer and semantic web specialist, working with leading organizations such as Elastic, ETH Zurich, Google (contract), Education First, and St George’s University of London, where I contributed to European research projects applying Semantic Web and Linked Data technologies in medical and educational contexts. My career has also included shaping user interfaces and AI-driven tools at Modulos AG (an AI startup based in Technopark Zurich) and contributing to the Swiss fintech industry, where I helped build scalable and performant web applications.