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System design interview question

Design a live sports scores site (ESPN/Cricbuzz)

Medium · System design (HLD)

The prompt

"Design a live sports score service. During a big cricket match, 50 million people have the scorecard open and every ball changes the score. Everyone should see the update within a couple of seconds. Most of the time, though, nothing is happening at all."

What this round really tests

extreme read amplification of a tiny mutable payload, plus the most brutal traffic skew in this entire list — near-zero baseline, 50 million concurrent during one match. The distinguishing insight is that the data is minuscule and identical for everyone, which makes this a caching and connection problem rather than a data problem.

Clarifying questions worth asking

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