WebAssembly Specification

Release 3.0 (2026-02-26)

Editor: Andreas Rossberg

Latest Draft: https://webassembly.github.io/spec/core/

Issue Tracker: https://github.com/webassembly/spec/issues/

• Introduction
  • Introduction
  • Overview
• Structure
  • Conventions
  • Values
  • Types
  • Instructions
  • Modules
• Validation
  • Conventions
  • Types
  • Matching
  • Instructions
  • Modules
• Execution
  • Conventions
  • Runtime Structure
  • Numerics
  • Types
  • Values
  • Instructions
  • Modules
• Binary Format
  • Conventions
  • Values
  • Types
  • Instructions
  • Modules
• Text Format
  • Conventions
  • Lexical Format
  • Values
  • Types
  • Instructions
  • Modules
• Appendix
  • Embedding
  • Profiles
  • Implementation Limitations
  • Type Soundness
  • Type System Properties
  • Validation Algorithm
  • Custom Sections and Annotations
  • Change History
  • Index of Types
  • Index of Instructions
  • Index of Semantic Rules

• Index of Types

• Index of Instructions

• Index of Semantic Rules

• Index