JAEGER

See the market behind every headline @Polymarket.

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About the Project

Inspiration

Prediction markets are becoming a major way to understand what people truly think will happen. But actually finding relevant markets while browsing the web still feels annoying. We kept reading articles about elections, sports events, and tech launches, and later realized there were already Polymarket markets for those exact topics.

We asked ourselves:

What if prediction markets could follow you around the internet?

That idea became Jaeger, a browser extension that surfaces the markets behind the headlines.

What We Built

Jaeger is a Chrome extension that automatically discovers relevant Polymarket markets for any webpage you visit. With one click, it shows:

  • Keyword matched markets based on page content
  • Volume, odds, and status tags
  • Filters by date, volume, and category
  • A clean black and gold premium UI with smooth motion

It also includes:

  • Base Account wallet onboarding
  • Light and dark mode toggle with saved preferences
  • Responsive design across sidebar widths

Browsing the web feels more interactive and informative once markets appear where information appears.

How We Built It

We built the interface using React 19 and bundled with Vite. The UI loads into the Chrome side panel. A content script named scrape.js extracts text signals from the active page and passes them to the background worker. The background script calls the Polymarket API and selects the most relevant markets for display.

Tech stack:

  • React 19
  • Vite
  • Wagmi v2
  • Base smart accounts for wallet onboarding
  • Chrome Extension API using Manifest Version 3

We separated logic across three parts of the extension which kept the architecture organized.

Challenges We Faced

Chrome extensions run across three independent execution contexts:

  • The UI inside the side panel
  • The content script inside each webpage
  • The background service worker

Each context has different rules for messaging, permissions, and network calls. This created challenges around communication flow, CORS, and maintaining a persistent wallet session. We also needed to scrape pages without interrupting site functionality.

We spent a lot of time in DevTools figuring out how to get each layer talking correctly.

What We Learned

  • How to structure a clean and modern Manifest Version 3 extension
  • How to design better communication between background scripts and UI
  • How smart contract wallets improve onboarding for new users
  • Prediction markets are much more useful when discovery is automated

We started this weekend experimenting with an idea. We ended up making something that feels like a real product.

What Comes Next

  • Better market matching using embeddings and contextual signals
  • User watchlists and notification alerts
  • Market movement analytics such as volume spikes and price changes
  • Publishing to the Chrome Web Store to gather real user feedback

Jaeger is only at the beginning. We want it to become the simplest path from information to market action.

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