Google Interview Process 2026 — Rounds, Tips & Questions

Design a URL shortening service (like bit.ly) that handles 1 billion shortened URLs and 100K redirects per second.

Our RAG pipeline responses are accurate in staging but hallucinate in production on long user queries. Walk me through how you debug and fix this.

A list of 50,000 items renders in a React component. Users scroll and experience jank. How do you fix it without pagination?

Given a binary tree, return the boundary of the tree in anti-clockwise direction starting from the root. The boundary consists of the left boundary, leaves, and the right boundary in reverse.

Design YouTube's video upload and processing pipeline. A user uploads a 4K video of 10GB. How does it become available in 360p, 720p, and 4K for streaming?

Design Google Search autocomplete. As a user types "wea", suggest "weather", "weather today", "weather London". Cover: trie vs inverted index, personalisation, freshness, latency budget (<100ms), and how you handle offensive query suggestions.

Design Google Maps ETA calculation. How do you compute the fastest route for 1B+ users in real time? Cover: graph representation of road network, Dijkstra vs A* vs Contraction Hierarchies, live traffic data ingestion, and how you handle road closures.

Implement Dijkstra's algorithm using a Fibonacci heap. Compare amortized complexity with a binary heap and explain when the Fibonacci heap is actually slower in practice despite the better theoretical bound.

Given a list of intervals, merge all overlapping intervals and return the result. Explain the sort-then-scan approach and the edge cases (touching intervals, single interval, all disjoint).

Explain how React's reconciliation algorithm decides what to re-render. A senior dev claims 'adding a key prop always makes things faster.' Is he right?