# event sourcing

CEFR C2 · Compound

Source: https://englishreference.com/word/event-sourcing
Updated: 2026-07-22

## Definition

a way of storing data where you keep a list of every change that happens instead of just the current state. It is like a bank statement that shows every transaction rather than just your final balance.

For teachers: an architectural pattern in which state changes are captured as a sequence of immutable events. Instead of overwriting the current state in a database, the system persists the full history of transitions to allow for reconstruction and auditing.

## Examples

- The bank uses event sourcing to track every deposit and withdrawal.
- By implementing event sourcing, the development team could easily debug the system by replaying the exact sequence of actions that led to the error.
- In high-compliance industries, event sourcing provides an inherent audit log, ensuring that the provenance of every data point is preserved and verifiable against the historical record of state transitions.

## Usage notes

- Commonly used in software engineering and distributed systems; often paired with the CQRS pattern.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.