System Design · sector

Messaging

Chat, calls and real-time delivery to billions of phones.

1 ready to open · 4 more on the way

WhatsApp's system design

The complete design: one open connection per phone, store-and-forward mailboxes, receipts as a state machine, a media road, end-to-end encryption — and how a team of about 50 ran it for 900 million people.

Core4 chapters · ~9 min

Coming next · 4 in the works

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