React Universe Meetup x Zalando, Berlin
Organizer
Speakers
Note: Registrations are now closed as we’ve reached full venue capacity (nice one, Berlin!). Follow us on X, LinkedIn, or Bluesky, or sign up for the Callstack newsletter to never miss a cool event in your area.
On January 29, 2026, we’re teaming up with Zalando to host an in-person React Universe Meetup at Zalando SE – BHW. Expect an evening built for experienced engineers who care about how things actually work in production, with time for both focused talks and unstructured conversations.
The event is aimed at software developers, senior engineers, and architects working across full-stack and cross-platform applications, with an emphasis on sharing practical lessons, architectural tradeoffs, and production-ready approaches. It’s a space for teams working with React Native and related technologies to compare notes, learn from peers, and take ideas back to their own codebases.
Agenda
- 6:00 PM Doors open
- 6:20 PM Welcome
- 6:30 PM Building a Video Experience with React Native: Lessons from Early Adoption by Eugene Verichev (Zalando)
- 6:55 PM LLM inference on-device in React Native: the practical aspects by Artur Morys-Magiera (Callstack)
- 7:20 PM How to Optimize your health with React Native, by Tejas Kumar (IBM)
- 7:45 PM Performance comparisons in Brownfield React Native projects by Mohit Karekar (Zalando)
- 7:55 PM Q&A
- 8:10 PM Networking
Talks abstracts
Building a video experience with React Native: Lessons from early adoption
This talk shares lessons from migrating to the new React Native architecture and how it enabled a more fluid, highly responsive video experience. Eugene will cover the architectural decisions behind the migration, the tradeoffs involved, and why an in-house solution proved to be the right choice at scale.
Eugene Verichev: Android Software Engineer at Zalando, Video Experience team. 10+ years in Android; previously Careem (Uber) and Grab.
LLM inference on-device in React Native: The practical aspects
This session explores the practical side of running LLM models locally on mobile devices in React Native apps. The talk focuses on three areas:
- Technical capabilities: Efficiency, performance, feature support, optimizations, and hardware compatibility
- End-user experience: Inference time, persistent memory usage, and device constraints
- Developer experience: Model formats, build-time considerations, and production readiness
The goal is to give teams a realistic view of what’s possible today, and where careful tradeoffs are still required.
Artur Morys-Magiera: Senior React Native developer at Callstack, PhD candidate in Automation & Robotics, and React Native contributor. Focused on open source, vision systems, AI, and low-level development.
How to optimize your health with React Native
This talk is a mix of health science and software engineering, showing us how we can use React Native and fitness trackers to optimize our health, recover better, manage stress, and unlock new levels of productivity and health.
Tejas Kumar: International keynote speaker, best selling author, and host of the developer-loved ConTejas Code podcast with an engineering background spanning 24 years, from AI to frontend to backend to devops. Today, Tejas shares talks with developer communities worldwide, equipping them to do their best work.
Performance comparisons in Brownfield React Native projects
How do you compare two experiences which look exactly the same but differ completely in their implementation? Defining a common screen-load performance metric is a challenge in brownfield projects. This talk shares how Zalando is solving this while reliably rolling out new screens with React Native.
Mohit Karekar: Part of Client Platform at Zalando, focused on frontend reliability, tooling and infrastructure.
About React Universe Meetups
React Universe Meetups are a series of in-person events focused on engaging with the community and connecting senior engineers, tech leaders, and decision-makers around the future of the React and React Native ecosystem.
Brought to you by Callstack, these meetups create space for practical, experience-driven conversations at the intersection of technology and business. The goal is simple: bring together people building and scaling real products, share what’s working (and what isn’t), and learn from peers who are deep in the work.
Talks are led by practitioners with hands-on experience in React, React Native, and related technologies, covering real challenges, tradeoffs, and lessons learned.
