System Design

CQRS and Event Sourcing for Ledgers

System Design diagram · made in Skemio

CQRS architecture showing commands appending immutable records to an Event Store, projected into a read database for query consumers.
CQRS architecture showing commands appending immutable records to an Event Store, projected into a read database for query consumers.
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What it shows

  • Ledgers store raw atomic deltas (+10, -5) in an append-only event store
  • Current balance states are calculated or projected, never overwritten
  • CQRS read projections serve sub-millisecond queries without table locks

The takeaway

Append-only event stores guarantee audit trails; materialized read projections make queries lightning fast.

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