HumanSignal

HumanSignal is the company behind Label Studio, one of the most widely adopted open-source data labeling tools. Formerly known as Heartex, the company develops both the free open-source project and a commercial enterprise offering, positioning itself around scaling human judgment for AI development.

What they provide

Label Studio is a flexible, self-hostable labeling tool that supports many data types in one interface, including text, images, audio, video, time series, and multimodal data. Its configurable labeling interfaces let teams set up annotation for tasks ranging from classification and object detection to named-entity recognition and LLM output evaluation. It integrates with machine learning models to supply pre-labels and support active learning, and exports to standard formats. HumanSignal also offers Label Studio Enterprise, a cloud and on-premises edition that adds team management, role-based access control, SSO, analytics, data discovery, security certifications, and support SLAs.

Where they fit

In the AI data supply chain, HumanSignal serves teams that want to own their labeling workflow with software rather than outsource it to a managed service. The open-source project is popular with practitioners, researchers, and engineers who need a free, adaptable tool they can run themselves, while the enterprise edition targets organizations that need governance, scale, and support. Increasingly, Label Studio is also used for evaluating and refining generative model outputs, extending its role from traditional data annotation into human feedback and quality assessment for LLMs.