Case study
TwentyThree
Video Marketing Platform
TwentyThree is an all-in-one video marketing platform combining webinars, video hosting, and analytics. Over two years I designed most of its views, features, and components — across the full platform redesign, the Webinars product, and the WebinarTray production timeline.
TwentyThree One Platform
Before the redesign, each core area of the platform — hosting, analytics, webinars — looked and behaved like a separate product. The task: take the design language we'd proven in Webinars and unify the entire platform around it.
I designed the majority of the platform's views, features, and components — turning the new direction into a working system screen by screen. The redesign replaced years of accumulated inconsistency with one cohesive, scalable interface, and the component library I built along the way still powers every new feature designed for the platform today.





TwentyThree Webinars
Webinars is the platform's flagship product — drag-and-drop planning, customizable templates, and real-time audience engagement with polls and Q&A. Its webinar room needed a full rethink, not a facelift.
I explored and prototyped multiple concepts for the new room and defined the user flows and interactions that made it into production. The result is a fully reimagined interface that stays clear for first-time hosts and flexible for power users running complex productions.


WebinarTray Feature
WebinarTray is a first-of-its-kind, drag-and-drop production timeline: hosts line up scripts, slides, videos, TV cards, and polls in the same environment they present in — planning and production finally live in one place.
I designed the Tray from a blank page: the first-time experience that shows every possibility upfront, the add-item flows for videos, images, notes and polls, the live states, and the element system behind them. Getting drag-and-drop to feel effortless inside a live production environment was the hardest design problem of the project.
The production version was consolidated from these explorations by my design lead — the interaction model and user flows I defined carried through to what shipped.
Design direction: Sander Kuypers · Built with the TwentyThree team
“Mateusz is one of those designers who can take over ‘I have this idea and here's what we know about it so far... Play with it and see if there's something?’ and put it together for you — and also a kind of top of the class UI designer who would execute the final pixels of everything with the last detail considered and systemise it.”
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