Fast front matter extraction and strict YAML-subset decoding for PHP.

ALTO Front Matter extracts document metadata, decodes a strict YAML subset, and exposes the result through typed accessors without retaining the document body.

It is designed for Markdown processors, static-site generators, content tools, and other applications that need predictable metadata without a general-purpose YAML runtime. Unsupported constructs fail explicitly with source coordinates.

Start

Work with data

  • Typed Metadata documents accessors, defaults, enums, and dates.
  • Decoding defines the accepted YAML subset and scalar typing.
  • Rendering creates YAML, JSON, or TOML front matter.
  • Integration covers the decoder and renderer contracts.

Reference

  • Errors explains the exception hierarchy and recovery boundaries.
  • Design records performance goals, guarantees, and limitations.