WebAssembly Specification — WebAssembly 3.0 (2026-06-08)

Navigation

Introduction

Structure

Validation

Execution

Binary Format

Text Format

Appendix

Index of Types

Index of Instructions

Index of Semantic Rules

Index

Download as PDF

Quick search

WebAssembly Specification¶

Release 3.0 (2026-06-08)

Editor: Andreas Rossberg

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

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

Introduction<br>Introduction

Overview

Structure<br>Conventions

Values

Types

Instructions

Modules

Validation<br>Conventions

Types

Matching

Instructions

Modules

Execution<br>Conventions

Runtime Structure

Numerics

Types

Values

Instructions

Modules

Binary Format<br>Conventions

Values

Types

Instructions

Modules

Text Format<br>Conventions

Lexical Format

Values

Types

Instructions

Modules

Appendix<br>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

©2017-2025, WebAssembly Community Group.