NVIDIA NeMo is a conversational AI toolkit built for researchers working on automatic speech recognition (ASR), natural language processing (NLP), and text-to-speech synthesis (TTS). The primary objective of NeMo is to help researchers from industry and academia to reuse prior work (code and pretrained models and make it easier to create new conversational AI models. NeMo is an open-source project, and we welcome contributions from the research community. The 1.0 update brings significant architectural, code quality, and documentation improvements as well as a plethora of new state-of-the-art neural networks and pretrained checkpoints in several languages. NeMo is a PyTorch ecosystem project that relies heavily on two other projects from the ecosystem: PyTorch Lightning for training and Hydra for configuration management.