Design a collaborative whiteboard like Figma
PremiumReal-timeHard
- CRDT
- Last writer wins per property
- Multiplayer cursors
Quick answer
This real-time interview question asks you to design a collaborative whiteboard like Figma. Aim for a design that delivers updates to many users with low delay, then explain connections, fan-out, ordering and trade-offs. Interviewers want to see how you keep latency low, handle reconnects and stay correct under load.
The problem
Design the multiplayer layer of a collaborative whiteboard and design tool like Figma or Miro. Up to 200 people can have a file open and 20 may edit at once, moving shapes, reordering layers and typing text with live cursors; the file must never differ between two screens, even after an hour of offline edits.
A file is a tree of objects (frames, groups, shapes, text, connectors), each with properties such as position, size, colour and parent. Everyone sees each other's cursors and selections, and a user who was offline on a train for an hour must be able to merge their work.
What must a collaborative whiteboard like Figma do?
- Edit objects: Create, delete, move, resize, restyle and reparent objects; edit text inside a text object.
- Live view: Other users' changes appear within 200 ms in the same region; drags look continuous, not jumpy.
How well must it do it?
- Convergence: After all changes are delivered, every client has an identical object tree.
- No lost work: Any change acknowledged to a user persists.
What scale should you design for?
Use these numbers in your estimates.
The scale numbers unlock with this questionUnlock
Key concepts
- CRDT
- Last writer wins per property
- Multiplayer cursors
- Fractional indexing
- Scene graph sync
- WebSocket
How you’ll practise
- Requirements
- Estimate
- Connections
- Message flow
- Delivery guarantees
- 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 real-time design round.
- Clarifies latency, ordering and delivery guarantees
- Chooses a connection model with reasons
- Explains fan-out to many receivers
- Handles reconnects, missed messages and duplicates
- Plans for hot spots and sudden traffic spikes
- States trade-offs between consistency and speed
Questions people ask about this interview question
- Which design type is this question?
- It is a real-time question. You design a collaborative whiteboard like Figma 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 who sends and receives updates, how fast they must arrive and what order matters. 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