Cosab

Cosab is an open-source software platform designed to enable collaborative annotation, curation, and sharing of textual and media-rich datasets and documents in research, education, and cultural heritage contexts. It provides tools for multi-user annotation, data governance, and reproducible workflows, aiming to support scholarly collaboration and public engagement with sources.

The name cosab is derived from Collaborative Annotation and Sharing Bridge, and in project documentation it is commonly written in lowercase. The term is used to denote both the platform and the broader concept of linked annotation and sharing within digital collections.

Core features of cosab include real-time multi-user annotation, versioned artefacts, fine-grained access control, and a pluggable architecture that supports text, images, audio, and structured data. It offers REST and GraphQL interfaces, integrates with common authentication providers, and stores provenance metadata to support reproducibility and accountability in research workflows. The platform emphasizes interoperability with metadata standards and data formats to facilitate exchange with external systems.

Architecture centers on a client-server model with a modular backend comprising an annotation engine, a data store, and a plugin manager. It supports pluggable storage backends (SQL databases and object stores) and event-driven synchronization to enable responsive collaboration. The architecture is designed to accommodate deployment in academic labs, museums, and digital humanities projects, from small teams to larger consortia.

History and governance: cosab began as an international community effort and was first released in 2018. It is maintained by a non-profit foundation with an elected technical steering committee and follows open-source governance practices that encourage community contributions and transparent decision-making.

Adoption and use: institutions widely use cosab to annotate primary sources, encode scholarly notes, and share annotated corpora. Ongoing development focuses on scalability, offline work, and enhanced interoperability with research pipelines. See also: digital annotation, data provenance, open-source software, collaborative platforms.