FiftyOne

FiftyOne by Voxel51 is an open-source toolkit for curating, visualizing, and evaluating computer vision datasets and the models trained on them. A Python library pairs with an interactive web app: users load images, videos, and labels, then filter, tag, and explore them, plot embeddings to find clusters and outliers, and evaluate predictions to surface failure modes and annotation mistakes. Integrations cover PyTorch, Hugging Face, and Ultralytics, plus annotation platforms like CVAT and Label Studio, and built-in Dataset and Model Zoos provide common benchmarks and pretrained models. Under the hood it uses MongoDB for scalable dataset storage, supports Python 3.10 through 3.13, and offers a plugin system for extending the app with custom panels and workflows. Apache 2.0 licensed and installable via pip or Docker, FiftyOne is used by computer vision engineers and ML researchers who need to understand why models fail and to improve dataset quality rather than simply collect more data.