Deck: a presentation engine with a live audience room
MDX slides with a live room on Cloudflare: presenter sync, polls, quizzes and drawing from the audience's phones, with nothing to install.
- What
- My own product
- Role
- Designer and engineer
- When
- Sep 2026
- per deck: phones follow, roam, vote, ask and draw
- 1 room
- exports from the same slides
- PDF · PNG · PPTX
The situation
I wanted my own presentation engine: slides written as MDX, and an audience that can follow along, answer polls and ask questions from a phone, without installing anything or signing in.
What I built
- An MDX compiler and React runtime with reveal.js/Slidev-level features: fragments, vertical stacks, code walkthroughs, themes and backgrounds.
- A live room per deck on a Durable Object with hibernating WebSockets: presenter sync, follow or roam, polls, quizzes, questions, drawing and confetti.
- Excalidraw sketches drawn from code, glossary term cards, and exports to PDF, PNG and PPTX.
- I presented my GIS project review with it.
Stack
- React
- TypeScript
- Vite
- MDX
- Durable Objects
- WebSockets
- D1
