Is your organization adopting Kafka as their messaging bus but you’ve found that it will take too long to migrate your existing service-oriented architecture to a log-oriented architecture? Some of the biggest challenges in building a new stream processor can be implementing all the business logic again. It has become increasingly common for companies with high-throughput source streams and change-data-capture logs to want to build systems fast. At Ticketmaster, we have found a solution to the problem by leveraging the business logic in our existing services and calling them from our Java based KafkaStreams processor applications in an efficient manner. In this talk, we will examine the initial challenges we faced in our transition, then we will explore the solutions we built to address the use cases at Ticketmaster. The primary focus will address our workflow around calling services to bring stream processor applications to market fast. We will review our challenges and share tips for success.