YOUR BRIEF
What to work through
Work through google Maps as a spoken system design interview. Start by clarifying the scope, sketch a working design and explain the trade-offs behind your choices.
- Users send location updates while they move
- Directions with an arrival time, for driving, walking and biking
- Render the map at any zoom level
- Reroute users when traffic or an incident makes a faster route
BEFORE YOU START
Constraints to discuss
- 1 billion daily users
- About 200,000 location updates a second, 1 million at peak
- Accurate directions and smooth map rendering
- Light on mobile data and battery
- Highly available
Need a starting point?
Watch for these common gaps as you prepare:
- One road graph for the whole world in memory
- Sending every GPS point as its own request
- Rendering tiles on every request instead of precomputing and caching them
- Mobile push as the channel for live reroutes