# Event Contract

> The agreed schema and semantics of an event that publishers and subscribers both honor.

Record: `lexicon:event-contract`
Kind: constraint
Layer: [Execution Core](https://banes-lab.com/records/layer/execution-core.md)
Canonical: https://banes-lab.com/ontology/lexicon#lexicon-event-contract

Listed in [Lexicon terms](https://banes-lab.com/api/records/lexicon.md), after [Deduplication Key](https://banes-lab.com/records/lexicon/deduplication-key.md) and before [Event Schema](https://banes-lab.com/records/lexicon/event-schema.md).

## Category

- [Event Messaging Async](https://banes-lab.com/records/lexicon-category/event-messaging-async.md)

## Required by

- [Event Bus](https://banes-lab.com/records/architecture/event-bus.md)

## Linked from

- [Event / Messaging / Asynchronous Architecture](https://banes-lab.com/ontology/principles/architecture-category-event-messaging-asynchronous-architecture.md)