YouTube Architecture

Uploading, transcoding and serving video to billions.

On the roadmap:Software Architect · step 5: Learn from the giants

Overview

YouTube ingests uploads, transcodes them into many formats and bitrates, and serves them through a global CDN. Vitess helped scale MySQL for metadata.

Architecture highlights

Asynchronous transcoding pipeline
Adaptive bitrate streaming
Vitess for sharding MySQL metadata
Global CDN and edge caching

Architecture diagram

Key components

Upload service
Resumable ingestion of large files
Transcoding workers
Convert to multiple codecs and resolutions
Metadata DB (Vitess)
Titles, comments and counters
CDN / edge caches
Serve popular videos near viewers
Recommendation system
Ranks the home feed

Challenges and trade-offs

Hot content
Viral videos produce traffic spikes that must be absorbed at the edge.
Storage growth
Hundreds of hours are uploaded every minute, each in many renditions.
Counter accuracy
View counts need eventual consistency with fraud filtering.

Study: YouTube

Learn how YouTube is built from the people who explain it. Watch first for the picture, then read for the detail.

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26 min

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Design Youtube - System Design Interview

NeetCode · 575K views

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