Kinds

A Kind is a meta-object that defines the structure, appearance, and interactions of a type of objects.

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Kind Object

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Metadata

The metadata of a kind contains essential information about its type and versioning. Every kind is minted from the Set of Kinds, with a kind of the Kind of Kind.

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Elements

Each kind has 6 elements, defined by the Kind of Kind. These elements serve as the core structure for both object typing and asset computation.

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Kind Contract

A Kind Contract is a Matter written in code form. It defines how an object’s assets are computed from its elements — enabling programmable logic for rendering, validation, or transformation.

Kind contracts are currently written in AssemblyScript, compiled to WebAssembly using kind-as. A Rust-based compiler is planned for future support.

@kind
class Hat {
  design: MatterImage;
  background: MatterImage;

  function meta(): Json {
    // return metadata
  }

  function picture(): Image {
    // image with background
  }

  function figure(): Image {
    // image without background
  }
}

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Elements

The fields of the contract class define the elements of the object. These can be accessed during kind contract execution:

design: MatterImage;
background: MatterImage;

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Facets

The methods exposed by the kind contract are called facet functions. Each facet function defines how a specific object asset is computed:

function picture(): Image {
  // image with background
}

Each output is called a facet image, and it can be accessed using a facet selector — a unique identifier used to dispatch to the correct function.

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Kind Registry