WebAssembly Specifications

To support the embedding of WebAssembly into different environments, its specification is split into layers that are specified in separate documents.

Core specification

Defines the semantics of WebAssembly modules and its instruction set, independent from a concrete embedding. The WebAssembly core is specified in a single document:

• Core: defines the structure of WebAssembly modules and its representation in binary and text format, as well as the semantics of validation, instantiation, and execution.

API specifications

Define application programming interfaces enabling the use of WebAssembly modules in concrete embedding environments. Currently, two APIs are specified:

• JavaScript API: defines JavaScript classes and objects for accessing WebAssembly from within JavaScript, including methods for validation, compilation, instantiation, and classes for representing and manipulating imports and exports as JavaScript objects.

• Web API: defines extensions to the JavaScript API made available specifically in web browsers, in particular, an interface for streaming compilation and instantiation from origin-bound Response types.