The request bodies for POST, PUT, or PATCH API requests must always have a schema defined using JSON Schema. There are some situations with binary and other formats where this isn’t possible, but the majority of request bodies should have a valid JSON Schema reference.
The JSON Schema for request bodies allow requests to be validated, examples generated, and are essential for testing APIs. Keep you request bodies well-defined and validated, and require exceptions to help drive the policies and rules you apply to request bodies across your APIs.