Open Graph protocol
What it is
The Open Graph protocol is a metadata vocabulary that lets a web page be represented as a rich object in a social graph. Its initial design is based on RDFa and uses <meta> elements in the page’s <head>, with developer simplicity as an explicit goal.
Key concepts
- Every page requires
og:title,og:type,og:image, andog:url; the URL is the object’s canonical permanent identifier in the graph. - Recommended optional metadata includes audio, description, determiner, locale and alternate locales, site name, and video.
- Structured properties add details such as a media item’s secure URL, MIME type, dimensions, and image alternative text.
- Repeating a meta property forms an array, while global and custom namespaced object types extend the type system.
How you’d use it
Add the four required properties to a page’s <head>, then supply optional and type-specific properties for the preview or graph object you need. Add structured media metadata after its root property, and provide og:image:alt when an Open Graph image is present.
LLM angle
none stated
Pitfalls & lessons
Some og:type values impose additional required properties. For repeated values, the first tag wins conflicts; structured properties must immediately follow the root value they describe, because a new root starts a new grouping. The protocol also says an Open Graph image should have alternative text.
Verdict
A deliberately small implementation target for turning ordinary pages into graph objects, with enough extension points for richer media and domain-specific types.
Sources consulted
- http://ogp.me/