Keras is an open-source software library designed to simplify the process of building and training artificial intelligence (AI) and machine learning models in Python. It provides a user-friendly interface for creating neural networks, making it accessible to both beginners and professionals. Keras acts as a high-level API that can run on top of popular deep learning frameworks like TensorFlow, allowing users to quickly prototype, test, and deploy sophisticated AI models without needing deep technical expertise in the underlying mathematics or code. Its modular approach and extensive documentation make it a popular choice for developing applications in image recognition, natural language processing, and more.