As a developer tools analyst, here is a comparison of Apache Pulsar and RisingWave for senior engineers: Apache Pulsar and RisingWave are two distinct open-source projects with differing focuses. In terms of momentum, RisingWave appears to be gaining traction more rapidly, having accrued 90 stars over the last 30 days compared to Apache Pulsar's 77, despite Pulsar's significantly larger overall star count (15,187 vs 8,873). This suggests RisingWave is currently attracting new attention at a faster rate. Community size is notably larger for Apache Pulsar, reflected in its substantial lead in overall stars, indicating a more established and broader user base. This larger community often translates to more extensive documentation, support resources, and potentially, more enterprise adoption. Use cases diverge significantly between the two. Apache Pulsar is primarily positioned as a distributed pub-sub messaging system, suitable for scalable, decoupled architectures, event-driven systems, and IoT applications. In contrast, RisingWave is a full-fledged streaming data platform, catering to real-time stream processing, low-latency serving, and Iceberg table management, making it more aligned with analytics, data integration, and real-time data processing workloads. Each project's design centers around different architectural needs, making the choice between them highly dependent on the specific requirements of the project at hand.