This thesis compares three modern JavaScript frameworks—Next.js, SvelteKit, and Astro—for e-commerce web development, focusing on how different rendering strategies (Static Site Generation, Server-Side Rendering, and Client-Side Rendering) affect performance metrics like load times, interactivity, and resource efficiency. Prototype e-commerce applications were developed using each framework, and performance testing was conducted to measure First Contentful Paint (FCP), Largest Contentful Paint (LCP), Interaction to Next Paint (INP), page size, and SEO-friendliness. Results show that Astro and SvelteKit consistently outperforms Next.js in load times and resource efficiency. However, the differences in performance metrics are not drastically large. All three frameworks are capable of delivering high-quality e-commerce applications. Therefore, decision-makers should also consider factors such as developer experience, community support, and specific project requirements when selecting a framework.