Design an offline maps app like Google Maps
PremiumMobile systemHard
- Vector tiles
- Offline region download
- Tile pyramid
Quick answer
This mobile system interview question asks you to design an offline maps app like Google Maps. Aim for a design that meets its requirements at the stated scale, then explain its main components, data flow and trade-offs. Interviewers want to see how you scope the problem, size it and defend each choice.
The problem
Design an offline maps app like Google Maps for iOS and Android. Users download a region, then view the map, search places and get turn-by-turn driving directions with no network at all. The hard parts are the download size, storage, offline routing and search, background navigation and keeping maps up to date.
Map data is prepared on the server. Design the app.
What must an offline maps app like Google Maps do?
- Download a region: The user picks an area up to 50 × 50 km, sees its size and downloads it on Wi-Fi in the background.
- Offline map: The map pans and zooms smoothly to street level inside downloaded regions with no network.
How well must it do it?
- Small downloads: A city region stays well under 150 MB.
- Smooth rendering: 60 fps panning on mid-range phones.
What scale should you design for?
Use these numbers in your estimates.
The scale numbers unlock with this questionUnlock
Key concepts
- Vector tiles
- Offline region download
- Tile pyramid
- Offline routing
- Mbtiles sqlite
- Delta map updates
How you’ll practise
- Requirements
- App architecture
- Data and offline sync
- Networking and push
- Performance, battery and releases
- Wrap-up
Lala, personalized to you, gives a hint when you ask and reviews your design when you are ready.
What do interviewers look for?
In any mobile system design round.
- Clarifies the requirements before drawing anything
- Uses a few numbers that actually change the design
- Draws a clear path from the client to storage
- Picks storage and caching with reasons, not by habit
- Explains what breaks first under load and how to fix it
- States trade-offs openly instead of claiming a perfect design
Questions people ask about this interview question
- Which design type is this question?
- It is a mobile system question. You design an offline maps app like Google Maps and explain your choices the way you would in an interview.
- Is this question asked at entry level?
- It is marked Hard. It suits engineers preparing for senior interviews, where you are expected to drive the discussion and go deep on trade-offs.
- What should I cover first?
- Start with the requirements: what the system must do, how well it must do it and which numbers change the design. Agree on scope with the interviewer before you design anything.
- Can I practise it for free?
- It is a premium question. Sign up and unlock it once for 10 credits; it then stays unlocked. When you finish, Lala, your personalized AI mentor, can review your design for 30 credits.
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Updated · Written by the SevyDevy team