Design
Multiplayer Game Matchmaking System
Design a matchmaking service that pairs players of similar skill into balanced game sessions at scale, with low wait times.
This is a Low-Level Design (LLD) problem. New to LLD vs HLD? Start here.
01 - Why interviewers ask this
It tests a genuine optimization trade-off (wait time vs. match quality) rather than a pure correctness problem — interviewers check if you can reason about tuning a system, not just building one.
02 - Where this system exists in the real world
You interact with this design every day.
Riot Games / Activision competitive matchmaking
Mobile multiplayer game matchmaking services
Esports ranked-ladder systems
03 - What you'll master
Solve this once. Know it forever.
Bucket players by skill rating for fast matching
Widen search criteria over time to bound wait
Treat pre-formed parties as a single matching unit
04 - What you'll design
6 functional · 3 non-functional requirements.
Queue a player for a match, optionally as part of a pre-formed party
5 more requirements inside
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05 - Companies that ask this
You may face this exact question in your next interview.
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