Consumer Messaging Platform — WhatsApp-Class System · View 18 of 23

Core Data Model

Thirteen entities covering accounts, devices, keys, conversations, envelopes, receipts and media — and the column that is conspicuously absent.

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No body column

message_envelope carries routing metadata and nothing else
Content exists only as ciphertext in device_inbox, until acknowledged
A database dump of the durable tier yields who messaged whom, never what

Device-centred

Inbox and receipt rows are keyed by device, not by account
This is what makes multi-device a schema property instead of a feature flag
device_key holds identity, signed and one-time keys in one table by key_type

Shown, not exhaustive

Keys, foreign keys and the columns needed to follow a join
Sharding keys, audit columns and soft-delete flags are omitted
Presence, typing and session state are cache structures, not tables