Proximity Service (Yelp)
Find nearby businesses within a radius for hundreds of millions of users.
Medium40 minGeohashRead replicasCaching
A proximity service answers "what businesses are near me?" for apps like Yelp or Google Maps. Business locations change rarely while searches are constant, so the design centres on a read-optimized geospatial index, aggressive caching, and replication.
Clarify requirements
Functional
- Search businesses near a location within a radius (0.5, 1, 2, 5, 20 km), optionally filtered by category and open-now.
- View business details.
- Business owners add, update, or remove listings; changes may appear by the next day (or within minutes as a bonus).
- Out of scope: reviews, photos pipeline, ranking ML (mention as extensions).
Non-functional
- 100M DAU, 200M businesses worldwide.
- Search p99 < 200 ms.
- High availability; read-heavy; eventual consistency for business updates is fine.
- Data privacy for user location (do not store precise history unnecessarily).
Try it first
Set a timer, sketch your own design on paper, then compare it with the reference walkthrough.
40:00
Defend it out loud
The AI interviewer will probe your design for Proximity Service (Yelp) and score it.