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LinkedIn system design interview questions

14 questions on this site are reported in LinkedIn software engineer interviews. Each has a full reference design (requirements, back-of-envelope numbers, components, user flows and deep dives with interviewer follow-ups). Each one can be walked through turn by turn and then sat as a mock. Patterns covered: fan-out, ranking, caching, social, multi-channel, idempotency, rate-limiting, priority-queues, algorithms, counters, redis, edge, tries, search, stream-processing, windowing, exactly-once, olap, analytics, recommendations, marketplace, exploration, append-only-log, partitioning, replication, consumer-groups, broadcast, pub-sub, sse, sampling, moderation, heavy-hitters, count-min-sketch, sliding-windows, hot-keys, inverted-index, scatter-gather, tail-latency, real-time, privacy, counting, time-partitioning, graph, sharding, in-memory, consistency, batch, clustering, ingestion, edge-caching, deduplication, experimentation, hashing, statistics.

Run an AI mock LinkedIn interview →One of these questions, run as a live round in that style, with a debrief at the end.

Attribution comes from public interview guides and candidate reports, not from LinkedIn. It indicates where a question has been asked, nothing more.

LinkedIn questions

What the LinkedIn round looks like

45–60 minutes, usually product-shaped around surfaces LinkedIn runs: the feed, messaging, notifications, search and typeahead, connection recommendations.

What it is reported to weigh

  • Product sense: what the member sees, judged alongside the architecture
  • The graph underneath: fan-out, and the skew between typical members and accounts with very large followings
  • Scale numbers for a member base of around a billion
  • Availability, security and how the system is run, not only how it is built

The common mistake

Making good choices silently. Interviewers are reported to score the reasoning they hear, so name the options, pick one, say why, and tie it back to what the member experiences.

From public interview guides and candidate reports, and LinkedIn’s own interview guidance where it publishes any. Not endorsed by LinkedIn. Formats change; treat it as a prior, not a promise.

How to prepare for the LinkedIn system design interview

Large-company loops run 45 to 60 minutes, expect numbers, and spend most of the time on deep dives. Walk through a question to see how a strong candidate paces the hour, sit the same question as a mock until you can produce the requirements, the estimates and the design without looking, then read the interview framework guide for how to structure the hour. The other questions on the site teach patterns that show up in LinkedIn interviews under different names.

Questions people ask about the LinkedIn system design interview

What system design questions does LinkedIn ask?

Questions reported in LinkedIn system design interviews include News Feed, Notification System, Rate Limiter, Search Autocomplete, Ad Click Aggregator, Project-to-Contractor Matching System, Distributed Message Queue and Live Comments, among 14 in total. Between them they test fan out, ranking, caching, social, multi channel and idempotency. The reports come from public interview guides and candidate accounts, not from LinkedIn, so practise the patterns rather than memorising one list.

What is the LinkedIn system design interview like?

45–60 minutes, usually product-shaped around surfaces LinkedIn runs: the feed, messaging, notifications, search and typeahead, connection recommendations.

What does LinkedIn look for in a system design interview?

Reports say the LinkedIn round weighs 4 things. 1. Product sense: what the member sees, judged alongside the architecture. 2. The graph underneath: fan-out, and the skew between typical members and accounts with very large followings. 3. Scale numbers for a member base of around a billion. 4. Availability, security and how the system is run, not only how it is built. Making good choices silently. Interviewers are reported to score the reasoning they hear, so name the options, pick one, say why, and tie it back to what the member experiences.

How do I prepare for the LinkedIn system design interview?

Practise the questions reported there out loud, under a 45-minute clock: requirements with numbers first, then estimates, a high-level design, and deep dives into the two or three hardest parts. Start with News Feed: watch a strong candidate answer it turn by turn, then sit it yourself. Then cover the patterns the round leans on (fan out, ranking, caching and social) with one more question each.