Label Studio

Label Studio is a widely used open-source labeling tool for text, images, audio, video and time series. HumanSignal, the company behind it, sells an enterprise edition with automation and team management.

Labeling interfaces are configured with XML-like templates, so the same tool handles named entities, bounding boxes, audio segments or LLM response ranking. An ML backend lets models pre-label data and learn from corrections. The enterprise edition adds reviewer workflows, analytics, SSO and AI-assisted labeling with language models.