Mol* web molecular graphics engine.

Web-based molecular graphics have transformed the interactive visualization of molecular data, leveraging modern web technologies that provide GPU acceleration, optimized JavaScript engines, and seamless access across devices without additional software installation. We present the graphics engine at the core of the Mol* toolkit, a high-performance, open-source framework that is widely adopted in academia and industry, including by the Protein Data Bank, UniProt, EMDB, and AlphaFold DB. The engine combines a comprehensive styling system with a suite of optimized rendering primitives, including real-time surface generation, to deliver both flexibility and visual fidelity. Efficient handling of large-scale molecular scenes is achieved through level-of-detail management, GPU instancing, spatial acceleration structures, and frustum/occlusion culling. A screen-space global illumination model provides scalable, high-quality lighting, while integrated AR/VR support enables immersive molecular exploration. Together, these capabilities enable engaging, real-time, high-fidelity visualization of molecular systems, across a wide range of scales, from single atoms to billion-atom mesoscale assemblies, demonstrating the strengths of a bespoke web-native rendering engine for molecular graphics, available at https://molstar.org.