Design LinkedIn
PremiumProduct architectureMedium
- Social graph
- Connection degrees
- Graph sharding
Quick answer
This product architecture interview question asks you to design LinkedIn. 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 LinkedIn, a professional network where members connect with each other, read a feed of posts from their network, and search and apply for jobs. The hard parts are showing the connection degree (1st, 2nd or 3rd) next to every name on a graph of a billion members, and building a ranked feed quickly.
What must the system do?
- Connect: A member sends a connection request with an optional note; when the other member accepts, both become 1st-degree connections.
- Degree badges: Every name in search results, profiles and the feed shows 1st, 2nd or 3rd degree, or nothing when farther away.
How well must it do it?
- Fast badges: Badges for a page of 25 search results add under 50 ms.
- Fast feed: The first feed page returns in under 400 ms at p99.
What scale should you design for?
Use these numbers in your estimates.
The scale numbers unlock with this questionUnlock
Key concepts
- Social graph
- Connection degrees
- Graph sharding
- News feed
- Job search
- Idempotent applications
How you’ll practise
- Requirements
- Core entities
- API design
- Client and server flow
- Scale and edge cases
- 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 product architecture 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 product architecture question. You design LinkedIn and explain your choices the way you would in an interview.
- Is this question asked at entry level?
- It is marked Medium. Entry-level engineers can practise it, but it expects you to reason about requirements and trade-offs, not only list components.
- 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