In plain language
It is the blueprint that says what valid data should look like before an automation accepts or sends it.
Example
A JSON Schema says an order must include an order_id string and a total number greater than zero.
Related terms
Field · JSON · Data Validation · Structured Output
Common misconception
A schema does not clean bad data by itself; it describes the rules, and something must validate data against them.
Implementation guidance
Define required fields and types, version schemas when they change, validate incoming payloads, and share the schema with every connected system.