Design a Geolocation Service

Requirements

• •Given an IP address, return the estimated geographic location (country, region, city, lat/lng)
• •Given a lat/lng and radius, return all points of interest within that radius
• •Support reverse geocoding: given lat/lng, return the nearest named location
• •Handle bulk IP lookup requests efficiently (batch API)
• •Update IP-to-location database weekly without downtime

Non-Functional Requirements

• •IP geolocation latency < 5ms (p99, cache hit)
• •Proximity query latency < 50ms for 10km radius
• •100,000 IP lookup requests/second
• •Weekly IP database update with zero downtime

Constraints

• •IP-to-location database is provided by a third-party vendor as a downloadable binary
• •The service is read-only; it does not ingest real-time location updates from devices
• •Accuracy requirement: city-level for IP geolocation (not street-level)

Evaluation Criteria