Poppin: prediction markets embedded into any webpage
A browser extension that brings Polymarket and Kalshi prediction markets onto the page being read, with trading, tracking and discussion alongside a publisher dashboard.
The product problem
Prediction markets usually live on their own sites. A reader who meets a relevant story has to leave the page, find the market and then return to keep reading. Poppin puts that market next to the content instead. Readers can see relevant markets, place trades and discuss outcomes without switching tabs, using markets from Polymarket and Kalshi on the page in front of them.
The delivered scope
The browser extension renders its interface inside a shadow root on the host page, with a background service worker, a popup, a side panel and a welcome flow. It carries page-level posts, comments, chat, follows and a leaderboard over a realtime connection. A Next.js dashboard lets publishers install an embeddable widget with a script snippet and manage its style, settings and announcements. NestJS, TypeORM, RabbitMQ, WebSockets and Firebase sit in the stack.
Overlaying a product on someone else's page
An extension that draws over arbitrary websites cannot assume anything about the host page's styles or scripts. Rendering inside a shadow root keeps the interface isolated, while the background worker owns connections and state across tabs. For a similar build, decide early which interactions belong in an in-page overlay, which belong in a side panel, and which belong in a separate web dashboard.
What shipped
A browser extension and publisher dashboard that bring prediction markets, trading and discussion onto existing webpages, backed by a realtime TypeScript backend.