Formatted as JSON
Principle
JSON is used as the format for all message payloads. It is not used for headers unless needed.
Description
This is a sensible default: JSON is used unless otherwise decided by a team and documented in a lightweight Architectural Decision Record (ADR) which is to be stored alongside the producer’s code in the repository.
Consequences
- Producers will have to include keys and objects in JSON structures, even when that value is going to be null. Not including it, would break the schema and therefore the contract.
- Consumers have to accommodate deserialisation (unmarshalling) of the JSON structure into strongly-typed types in their codebase.
- Regardless of technology choices, message formats are widely compatible and lightweight enough to be processed quickly.
Example
Correct
MILEAGE_UPDATED_EVENT {
mileage: 12345
}
Incorrect
MileageUpdated:
mileage: 12345