26linked

26linked is a theoretical open standard and reference implementation for building lightweight knowledge graphs. The project proposes representing entities as nodes and their relationships as directed edges, with the edge type restricted to a fixed set of 26 relation types labeled A through Z. This design emphasizes simplicity and interoperability, enabling easy data exchange across systems while remaining compatible with common linked-data formats.

The core data model comprises nodes, edges, and metadata. Each node represents a distinct entity and may carry optional attributes such as labels, identifiers, and provenance information. Each edge connects two nodes and carries a type from A–Z, along with optional provenance, timestamps, and versioning data. Graphs can be serialized in JSON-LD-compatible form and published with immutable identifiers for reproducibility. A lightweight query mechanism, dubbed 26QL, supports common traversals, filtering, and basic aggregations.

Development is community-driven, with contributors outlining the specification and providing reference implementations in JavaScript, Python, and Rust. The project emphasizes extensibility, privacy, and provenance verification.

Used in practice, 26linked is employed in digital libraries, citation networks, education repositories, and cultural heritage projects where a compact graph model suffices. It serves as a complement to larger standards such as RDF when the goal is rapid interlinking and straightforward visualization. Limitations include restricted expressivity due to a fixed relation set and potential fragmentation if adopted alongside other graph standards.