Design a geo-proximity service that finds the nearest places to a user, like Yelp or store locators.

Find the 20 nearest restaurants within 5km, fast, for millions of users. A naive distance scan over every place is hopeless. The design centers on spatial indexing, geohash or quadtree partitioning, and coping with dense cities versus empty regions. Here is how proximity search works.

Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.