Choose Messaging Tools by Requirements, Not Habit: Service Bus vs Event Grid vs Kafka

Many engineering teams default to familiar messaging tools from past projects rather than selecting infrastructure based on actual system requirements. Azure Service Bus, Event Grid, and Kafka each solve distinct problems: Service Bus handles reliable ordered delivery for business transactions, Event Grid manages reactive event routing with low-latency fan-out, and Kafka serves high-throughput streaming and event replay use cases. While platform teams often standardize on a single tool to reduce operational complexity, forcing one technology across all messaging patterns creates hidden architectural costs. A production system with varied communication needs — ordered workflows, infrastructure events, and data ingestion — may legitimately require all three tools running in parallel. The key decision factor should be the data contract each use case demands, not organizational familiarity or a desire to minimize the technology stack.