You can use collections data endpoint to insert one data item to that collection. This type of ingestion can be applied to any type of source.
Body
Body should contain JSON formatted data for collection to which you insert this data item. Key should be field name, value should match field type. If you have conflicting data types in one union (for example ["string", "long", "double"]) you should wrap value to confirm data type: {"fieldName": {"double":3.14}}. There is no need to wrap data if you use nullable fields like ["null", "long"]. Nested fields, arrays, maps should be created in usual JSON formatted way. Fields can appear in any order, fields that are not presented in collection's schema will be ignored.
Success Response
201 CREATED
status code will be returned.