PolygrAI is an advanced digital multimodal polygraph that fuses psychological principles with cutting-edge artificial intelligence and computer vision technology. By analyzing visual, audio, and linguistic cues, it identifies behavior fluctuations in real-time that may indicate stress or deception. This technology not only enhances the accuracy of deception detection but also provides valuable insights for decision-making in various application scenarios. Background research supporting PolygrAI includes studies by Barathi (2016) and Ding et al. (2019), demonstrating the effectiveness of multimodal approaches in detecting deception. The product does not collect user data, prioritizes privacy protection, and is developing a mobile version.