I love DuckDB from a product perspective and appreciate the engineering excellence behind it. However, DuckDB was primarily built for seamless for in-process analytics, data science, data-preparation/ETL workloads than real-time customer facing analytics.

ClickHouse’s bread and butter is real-time analytics for customer-facing applications, which often come with demanding concurrency and latency requirements.

Ack, totally makes sense that both are amazing technologies - you could try both and test them at the scale your real-time application may reach, and then choose the technology that best fits your needs. :)