RDF (Resource Description Framework)

RDF (Resource Description Framework) is the W3C standard for describing information about things as simple statements called triples. MLforSEO’s example is the film Tenet: Tenet, directed by, Christopher Nolan. Most SEOs never write RDF by hand, but the JSON-LD you add to pages is an RDF syntax, and the schema.org vocabulary is built on the RDF data model, so it explains why structured data behaves the way it does.

How it works

Each RDF statement has three parts:

• Subject: the thing being described.
• Predicate: the property or relationship (directed by, works for, founded).
• Object: another thing, or a literal value such as a name, date or number.

Things are named with IRIs (web identifiers, usually URLs), which can appear in any position; literals only appear as objects. A set of triples forms a graph, and triples that share an IRI join up, which is how a knowledge graph grows. The same graph can be written in several syntaxes, including Turtle, N-Triples, RDF/XML and JSON-LD, and queried with SPARQL.

MLforSEO frames the web’s structured data stack as three layers: schema.org as the shared vocabulary (launched in 2011 by Google, Microsoft and Yahoo), JSON-LD as the format you implement (2014), and RDF as the underlying model (first standardised by the W3C in 1999). The current core spec is RDF 1.1 (2014). RDF 1.2, a Candidate Recommendation as of April 2026, adds triple terms for making statements about statements.

How it’s used in SEO and marketing

• Understanding @id: in JSON-LD, @id is the IRI of a node. Reusing the same @id across pages is what merges scattered mentions into one entity (entity relationships depend on it).
• Querying Wikidata: Wikidata is a public RDF database, so you can use SPARQL to pull facts about your brand, competitors or a topic’s entities for research and audits.
• Debugging markup: converting JSON-LD to triples shows exactly which statements a parser reads, and which nodes are disconnected.
• Thinking in triples: MLforSEO’s EAV model work plans content as entity, attribute and value facts, the same shape search engines store.

Example

A Person block in JSON-LD with "@id": "https://acme.com/#jane" and "worksFor": {"@id": "https://acme.com/#organization"} produces one triple: the IRI for Jane, the schema.org worksFor property, the IRI for Acme. If another page describes Acme with the same @id, its facts attach to the same node. Without the @id, a parser creates a blank node that nothing else on your site can point to.

Limitations and things to watch

• Valid RDF only means the statements are well-formed; they can still be wrong or contradict other sources.
• Search engines support a subset of schema.org for rich results, so valid triples do not guarantee any search feature.
• Changing IRIs breaks the graph, so keep @id values stable once published.
• RDF 1.2 is not yet a final Recommendation as of the source date; check the W3C status before relying on new features.

Learn it on MLforSEO

• How Structured Data Reinforces Entity Understanding in AI Search
• What Schema.org @id Does and Why Your Entity Graph Falls Apart Without It
• Wikidata for Brands: Notability Criteria and a Realistic Path
• Structured Data Automation with Python
• AI Search & LLMs: Entity SEO and Knowledge Graph Strategies for Brands (course)