Bulk API requires master_key as api key and built for importing the data without any rate limiting unlike event/batchThis endpoint accepts application/json and the data format is same as event/batch. Additionally it supports application/x-rawjson for JSON dump data, application/x-ndjson for newline delimited JSON, application/avro for AVRO and text/csv for CSV formats. You need need to set 'collection' and 'master_key' query parameters if the content-type is not application/json.