Dioptra is an open-source data management and annotation platform that provides data filtering and annotation services for computer vision, natural language processing, and language models. Users can register and upload their own data, use Dioptra's data diagnostics tools for model debugging and regression testing, and use its active learning algorithm to filter out the most valuable unlabeled data. Dioptra also provides an API interface, making it easy for users to integrate with the annotation and retraining process. By using Dioptra, users can improve the accuracy of their models on difficult cases, shorten the training cycle, and reduce annotation costs.