We presented the latest innovations of HtmlFlow at the 19th International Conference WebIst in Rome on October 17th. Our work, titled "Enhancing SSR in Low-Thread Web Servers" demonstrates how to achieve progressive rendering when dealing with asynchronous data models and non-blocking APIs. Our approach, implemented on top of HtmlFlow, effectively overcomes the limitations of existing methods. We conducted evaluations against state-of-the-art reactive servers, particularly WebFlux, and compared it with popular templating idioms such as Thymeleaf and KotlinX.html. https://www.scitepress.org/Link.aspx?doi=10.5220/0012165300003584