Built a Chrome extension that finds Indian rental flats near all your key locations simultaneously

Got tired of the same problem every time I searched for a flat in Bangalore. Found something great near work, opened Google Maps, and realised it was 45 minutes from everything else I cared about. Repeat for every listing. Repeat for weeks.

So I built PropRadar.

You pin up to 5 locations on a map — office, gym, school, parents' home, wherever — and Gemini AI searches 99Acres, MagicBricks, and NoBroker simultaneously for properties that are close to all of them. Results show road distance to each of your locations and a combined commute score so you can compare at a glance.

The interesting technical bits:

Chrome's Manifest V3 CSP blocks all external script CDNs with no exceptions — not even trusted ones like cdnjs. So I couldn't use Leaflet. Ended up writing a complete tile map library from scratch (~460 lines) that implements the same API. The map runs on OpenStreetMap and CartoDB Dark Matter tiles, completely free.

Also, coded to extract partial results.

For key storage, AES-256-GCM with a key derived from the extension's unique install ID via PBKDF2. Even if someone dumps browser storage the ciphertext is useless without that specific extension install.

Ended up with zero permissions in the manifest — Chrome Web Store kept rejecting storage and tabs as unnecessary. Switched to localStorage (scoped to the extension origin, no permission needed) and confirmed chrome.tabs.create() works without declaring tabs.

Stack: Vanilla JS, OpenStreetMap + CartoDB tiles, Nominatim geocoding, Google Gemini API, AES-256-GCM encryption. No frameworks, no build tools, no backend.

It's free. You need a free Gemini API key from Google AI Studio — takes 2 minutes to get.

Currently supports Bengaluru, Mumbai, Delhi/NCR, Hyderabad, Chennai, Pune, Kolkata, Ahmedabad.

Chrome Link

Happy to answer questions about the build and take feedback.