"This paper examines multi-threaded Kafka producer applications, and how the performance of such applications is affected by how the number of producer instances relates to the number of executing threads. Specifically, the performance of such applications when using a single producer instance, shared among all threads, and when each thread is allotted a separate, private instance, is compared. This comparison is carried out for a number of different producer configurations and varying levels of computational work per message produced.Overall, the data indicates that utilizing private producer instances results in highe rperformance, in terms of data throughput, than sharing a single instance among the executing threads. The magnitude of this difference is affected, to some extent, by the configuration profiles used to create the producer instances, as well as the computational workload of the application hosting the producers. Specifically, configuring producers for reliability seems to increase the difference, and so does increasing the rate at which messages are to be produced.As a result of this, Brod, a wrapper library [56], based on an implementation of a client library for Apache Kafka [25], has been developed. The purpose of the library is to provide functionality which simplifies the development of multi-threadedKafka producer applications."