World Wide Web Consortium (W3C) brings a new language to the Web as WebAssembly becomes a W3C Recommendation

Author(s) and publish date


Following HTML, CSS and JavaScript, WebAssembly becomes the fourth language for the Web which allows code to run in the browser

Read testimonials from W3C Members — 5 December 2019 — The World Wide Web Consortium (W3C) announced today that the WebAssembly Core Specification is now an official web standard, launching a powerful new language for the Web. WebAssembly is a safe, portable, low-level format designed for efficient execution and compact representation of code on modern processors including in a web browser.


webassembly black and white logo

The arrival of WebAssembly expands the range of applications that can be achieved by simply using Open Web Platform technologies. In a world where machine learning and Artificial Intelligence become more and more common, it is important to enable high performance applications on the Web, without compromising the safety of the users.

Philippe Le Hégaret, W3C Project Lead

High-performance applications relying on a low-level infrastructure

At its core, WebAssembly is a virtual instruction set architecture that enables high-performance applications on the Web, and can be employed in many other environments. There are multiple implementations of WebAssembly, including browsers and stand-alone systems. WebAssembly can be used for applications like video and audio codecs, graphics and 3D, multi-media and games, cryptographic computations or portable language implementations.

WebAssembly enhances Web Performance

WebAssembly improves Web performance and power consumption by being a virtual machine and execution environment enabling loaded pages to run as native compiled code. In other words, WebAssembly enables near-native performance, optimized load time, and perhaps most importantly, a compilation target for existing code bases.

Despite a small number of native types, much of the performance increase relative to JavaScript derives from its use of consistent typing. WebAssembly leverages decades of optimization for compiled languages and its byte code is optimized for compactness and streaming. A web page can start executing while the rest of the code downloads. Network and API access occurs through accompanying JavaScript libraries. The security model is identical to that of JavaScript.

Future versions already in the works

The WebAssembly Working Group and the companion Community Group, where requirements gathering and language development take place, are already working on a range of features for future versions of the standard, including:

Threads provide the benefits of shared-memory multi-threading and atomic memory accesses.
Fixed-width SIMD
Vector operations that execute loops in parallel.
Reference types
Allow WebAssembly code to directly reference host objects.
Tail calls
Enable calling functions without using extra stack space.
ECMAScript module integration
Interact with JavaScript by loading WebAssembly executables as ES6 modules.

There are many other longer-term projects including several aimed at improving the usability and availability of WebAssembly. For example garbage collection, debugging interfaces, and WebAssembly System Interface (WASI), which is a set of modules for low-level system functionality such as file and network access.

WebAssembly joins the many W3C standards that define an Open Web Platform for application development with unprecedented potential to enable developers to build powerful, interactive experiences that are available on any device.

About the World Wide Web Consortium

The mission of the World Wide Web Consortium (W3C) is to lead the Web to its full potential by creating technical standards and guidelines to ensure that the Web remains open, accessible, and interoperable for everyone around the globe. W3C well-known standards HTML and CSS are the foundational technologies upon which websites are built. W3C works on ensuring that all foundational Web technologies meet the needs of civil society, in areas such as accessibility, internationalization, security, and privacy. W3C also provides the standards that undergird the infrastructure for modern businesses leveraging the Web, in areas such as entertainment, communications, digital publishing, and financial services. That work is created in the open, provided for free and under the groundbreaking W3C Patent Policy. For our work to make online videos more accessible with captions and subtitles, W3C received a 2016 Emmy Award. And for its work to standardize a Full TV Experience on the Web, W3C received a 2019 Emmy Award.

W3C's vision for "One Web" brings together thousands of dedicated technologists representing more than 400 Member organizations and dozens of industry sectors. W3C is jointly hosted by the MIT Computer Science and Artificial Intelligence Laboratory (MIT CSAIL) in the United States, the European Research Consortium for Informatics and Mathematics (ERCIM) headquartered in France, Keio University in Japan and Beihang University in China. For more information see

End Press Release

Media Contact

Amy van der Hiel, W3C Media Relations Coordinator <>
+1.617.253.5628 (US, Eastern Time)

Testimonials from W3C members

360Alibaba GroupAgora.ioBaiduHuaweiTencentXiaomi


"WebAssembly 规范的推出,进一步拓展了 Web 技术的应用 场景,让以往无法想象的应用成为可能,也为开发社区提供了更多选择, 为提升用户体验提供了技术保障。WebAssembly 标准的正式发布,让 Web 技术社区不再满足于浅尝辄止的保守应用,终于可以大胆地将其作为一个 正式的选型方案,这也势必会大力推进相应行业场景的发展。期待在 WebAssembly 标准化的推进过程中看到更多的 WASM 应用大放异彩。 "

胡尊杰,360 奇舞团 Web 前端技术经 理

Alibaba Group

"Alibaba is pleased to see that WebAssembly finally becomes a W3C Recommendation. We hope this new standard could trigger more innovation from the developer community as well as to enrich the functionality and experiences of the Web."

Hongru(Judy) Zhu, W3C Advisory Board Member, General Manager of Standardization Department, Alibaba Group

"WebAssembly makes it possible to provide strong computing capabilities on Web. It will exceedingly expand the application scenario of Web Apps, and rapidly increase the chance of developing compute-intensive Apps including real-time video/audio processing, hardcore games and AI with Web technologies. As an RTC service provider, Agora is devoted to deliver services with better real-time performance. We have released products based on WebAssembly, which enhances the performance and compatibility of video stream processing. We belief WebAssembly will be the most important option for Web developers to implement high performance Web Apps."

Chun Gao,Senior Architect of Agora


"热烈祝贺 WebAssembly 标准正式发布!百度一直是 W3C 的坚定支持者和参与者、贡献者和先行者,在 WebAssembly 的 runtime 平台技术、小程序小游戏和区块链技术等各个方面都有不错的应 用。随着标准的发布,我们将继续联合产业同仁一起打造开放、平等、协 作、分享的 Web 新生态。也期待 WebAssembly 标准能为 Web 新生态的繁 荣注入全新动力!"

吴萍,百度 App 主任架构师


"Congrats to this new milestone of WebAssembly. We believe it’s a very promising technology - it enhances the performance of Web and also acts as a nice bridge between Web and non-Web platforms. We look forward to more adoptions of WebAssembly in practice."

Zhiqiang Yu,W3C Advisory Committee Representative of Huawei


"Web 的能力越来越强,承载的业务越来越复杂,需要的 计算能力也越来越高。随着 WebAssembly 技术飞速发展,我们终于迎来了 WebAssembly 标准的正式发布。2008 年我们迎来了 Web 性能的第一次飞 跃 JIT 技术,如今 WebAssembly 将再一次大幅提升 Web 性能。我们得以 将更多桌面端的软件高效地移植到 Web,同时也可以在 Web 中使用 C/C++、Rust、Go 来优化需要大量计算的模块。WebAssembly 技术日益成 熟,将促进更多的应用从桌面延伸到 Web,这将赋予本就十分强大的 Web 更加丰富的功能!"

于涛,腾讯技术总监、 Alloyteam 负责 人


"WebAssembly 的标准化为 Web 技术的发展奠定了坚实 的基础,极大地扩展了 Web 应用的边界,解决了传统应用的可移植性问题, 提升了 Web 应用性能。 作为 W3C 会员,小米将继续支持和探索 WebAssembly 标准的落地应用,包括在浏览器、小游戏等重要场景支持 WebAssembly 。未来小米将持续在业务场景中进一步支持 WebAssembly 的 标准化发展。"

周珏嘉,小米集团技术委员会技术总 监

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