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TikTok (For You Feed) vs URL Shortener

TikTok (For You Feed)

TikTok (For You Feed)

Video pipeline, ML-driven recommendation, infinite scroll.

Components (10)

  • Mobile Client
  • CDN
  • API Gateway
  • Feed Service
  • Upload Service
  • Ranking Worker
  • Transcode Worker
  • Kafka
  • S3
  • Cassandra

Headline numbers

  • Watch events / sec~580K avg
  • Storage / day~3 PB
  • Recommendation inferences / sec~580K
URL Shortener

URL Shortener

Hashing, key generation, read-heavy caching.

Components (6)

  • Client
  • API Gateway
  • Write Service
  • Read Service
  • Redis
  • Postgres

Headline numbers

  • Write QPS (avg)~1,200/sec
  • Read QPS (avg)~120,000/sec
  • Storage per year~5 TB

Key differences

Only in TikTok (For You Feed)
  • CDN
  • Kafka
  • S3
In both
  • Client
  • Api Gateway
  • Service
  • Database
Only in URL Shortener
  • Redis

Flow shape

TikTok (For You Feed) flows
  • Scroll the For You feed5 steps
  • Upload a video6 steps
  • Transcode workers are overloaded4 steps
URL Shortener flows
  • Shorten a URL3 steps
  • Resolve short URL (cache hit)3 steps
  • Resolve short URL (cache miss)4 steps
  • Redis is down4 steps