Microformats

Microformats are a family of simple, open data formats for embedding structured information in HTML pages. They use ordinary HTML markup augmented with specific class names and rel attributes to encode metadata about people, events, products, reviews, and other items in a way that is both human readable and machine readable.

Initiated in the early 2000s by a community led by Tantek Çelik, microformats are maintained by the Microformats organization. The goal is to enable data portability and interoperability across applications without requiring RDF, namespaces, or specialized parsers. Microformats are designed to be easily discovered by search engines and other tools while keeping the content intact for readers.

Two generations exist: Microformats 1 and Microformats 2. The latter emphasizes a naming convention based on class attributes, using prefixes such as p- (plain text properties), u- (URLs), e- (HTML content), along with semantic wrappers like h-card (people and organizations), h-entry (blog entries), h-event (events), and h-review or h-recipe for specific content types.

Implementation is straightforward: mark up content with the appropriate classes (for example, h-card or h-entry) and optional rel values to indicate relationships such as author or predecessor. This approach preserves readability and requires no special syntax beyond HTML.

Common formats include h-card for contact information, h-calendar/h-event for events, h-entry for posts and articles, h-review for reviews, and h-recipe for recipes. Microformats 2 is widely cited as the most current version.

While microformats influence early search-engine optimization and data portability, adoption has varied. Schema.org, JSON-LD, and RDFa offer broader expressiveness, and many sites prefer those formats today. Microformats remain valued for their simplicity and compatibility with standard HTML.