CompMix is a research-driven tool designed to enable robust, efficient, and interpretable question answering over diverse and complex knowledge sources, including knowledge bases, text corpora, and web tables. Developed by an academic group led by Rishiraj Saha Roy at the Max Planck Institute, CompMix targets researchers and advanced practitioners interested in cutting-edge methods for conversational and complex question answering, leveraging heterogeneous data and state-of-the-art AI frameworks. The tool and its ecosystem provide unified frameworks, benchmarks, and implementations for advanced QA research.