Design a News Feed – Trade-offs

Pull vs Push

	Pull (fan-out on read)	Push (fan-out on write)
Read latency	Higher for large follow graphs	Low, precomputed
Write latency	Low	Higher, must fan out
Storage	Lower	Higher (feed per user)
Best for	Few follows, simple feed	Many follows, hot feed

Hybrid

Many systems use a hybrid: push for celebrity/influencer posts, pull for long tail.

Inline Check 1

What is the main trade-off between push and pull model for feeds?

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