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Part One: Exploring WebAssembly to Power Secure, Portable Applications Spanning the Cloud to Tiny Edge Devices

Stephen Berard

Origin and Key Considerations 


WebAssembly, commonly called Wasm, is a powerful technology revolutionizing how applications are built and deployed due to its efficiency in abstracting hardware and enabling reusable code. Initially developed for web browsers to address the limitations of JavaScript, Wasm has found its way into everything from cloud-native applications to the Amazon Fire TV, and more recently, tiny edge devices like Sony Midokura cameras and sensors. At its core, WebAssembly is a binary instruction format that serves as a portable runtime and compile target with support for many programming languages. This means developers can write code in their language of choice such as C/C++, Rust, Go, etc. and compile it to Wasm, then run it efficiently in web browsers or other runtime environments. 


I’ve previously outlined how Atym is leveraging WebAssembly as part of the Linux Foundation’s Ocre project to enable OCI-type app containerization on resource-constrained edge devices with as little as 1MB of memory.

Ocre Runtime Powered by Wasm 
Ocre Runtime Powered by Wasm 

In part one of this two-part blog, I’ll walk through a high-level overview of WebAssembly and the key elements of the technology that make it attractive for use cases outside of the browser.  Part two dives even further into the underlying technology, including the developer experience.    

  

Origin Story 

WebAssembly’s origins are deeply rooted in the evolution of the web. Early on, the web was primarily used for static content and simple interactions. Over time, it transformed into a platform capable of hosting rich, interactive experiences, from video streaming services to complex single-page applications (SPAs). This has commonly been referred to as “Web 2.0”.  While JavaScript enabled much of this innovation, its limitations became apparent as developers began pushing the boundaries of what the web could handle. 


The introduction of asm.js in 2013 marked a significant milestone in addressing these challenges. A subset of JavaScript, asm.js was developed by the Mozilla team as a proof-of-concept to show that web applications could achieve near-native performance. By compiling languages like C and C++ into a highly optimized form of JavaScript, asm.js allowed developers to create high-performance applications such as 3D games and CAD tools that efficiently ran directly in the browser. Notable examples include the Unreal Engine demo and Epic Citadel, both of which demonstrated the potential of the web as a gaming platform. 


While asm.js succeeded in unlocking new capabilities, it had inherent limitations. At its core, it was still JavaScript, which meant it relied on the browser’s JavaScript engine and suffered from its shortcomings.  This includes overhead related to garbage collection and JIT compilation, inconsistent performance across JavaScript engines, numerical computation overhead, and many more.  While it proved what was possible, developers were in search of a technology that could leverage the performance of native code while maintaining the safety and portability of the web. 


WebAssembly emerged in 2015 as the answer to this need. Developed through a collaboration between major browser vendors—Mozilla, Google, Microsoft, and Apple—WebAssembly took the foundational ideas of asm.js and reimagined them as a new binary instruction format. This format is compact, efficient, and can execute in a dedicated runtime environment, free from the constraints of JavaScript. With WebAssembly, developers are able to achieve near-native performance without compromising the portability and safety that are hallmarks of the web. 

By the time WebAssembly reached its 1.0 milestone in 2017, it was already supported by all major browsers, ensuring broad compatibility. Its introduction marked a turning point for web development, as it provided a unified solution for creating high-performance applications that could run seamlessly across platforms.  


WebAssembly’s origins in the web and its development through an open process highlight its commitment to transparency and collaboration. From its inception, Wasm has been shaped by a global community of contributors, fostering a truly collaborative development approach. Managed through the W3C, WebAssembly is built as an open standard, ensuring that its evolution is guided by the needs of developers, organizations, and the broader tech ecosystem rather than being driven by proprietary interests. This openness promotes interoperability, reduces barriers to entry, and empowers innovation across diverse fields. 

  

Beyond the Browser: WebAssembly and WASI 

While WebAssembly’s initial design focused on the browser, its utility quickly expanded to other environments. Developers began recognizing its potential to run secure, efficient, and portable applications outside of browsers, paving the way for WebAssembly to enter new areas like cloud-native applications spanning the cloud to IoT and edge  computing devices. This led to the introduction of the WebAssembly System Interface (WASI). WASI provides a standardized way for WebAssembly modules to interact with operating system resources such as the file system, network, and system clock, all while maintaining WebAssembly’s secure sandbox and portability. 

 

WASI transforms WebAssembly into a general-purpose runtime, enabling developers to build applications that can run across diverse platforms without modification. For example, WebAssembly modules running on WASI can power serverless functions, edge computing workloads, or even containerized applications. This portability makes WebAssembly an attractive alternative to traditional container technologies like Docker, as its smaller size and faster startup times reduce overhead while still maintaining isolation and security.  


This combination of performance and versatility has positioned WebAssembly as a game-changer in the tech landscape. It not only fills the gap left by JavaScript for computationally intensive tasks but also opens new doors for innovation across a range of industries. 

  

Why WebAssembly? 

The following are reasons why developers and organizations are utilizing WebAssembly. 


A Unified Development Experience Across Platforms 

In an increasingly heterogeneous computing landscape, organizations often struggle to maintain consistent application performance and behavior across diverse platforms, environments, and architectures. Traditionally, multi-architecture containers have been used to address this challenge by providing images tailored to specific CPU architectures, such as x86, ARM, or RISC-V. However, these containers can introduce significant overhead, requiring developers to build and manage separate versions of their applications for each architecture and OS. This process increases complexity in CI/CD pipelines and can inflate image sizes due to architecture-specific dependencies. 


WebAssembly offers a streamlined alternative by providing a single, platform-agnostic runtime. Applications compiled to Wasm are architecture-independent, allowing them to run seamlessly on servers, edge devices, and embedded systems without the need for separate builds. This not only eliminates the need to manage multiple architecture-specific images but also reduces engineering overhead and simplifies deployment pipelines. By enabling developers to truly build once and deploy anywhere, WebAssembly increases consistency across deployments while minimizing operational complexity. 

 

The Component Model introduces a standardized way to define composition and manage imports/exports between Wasm components, enabling developers to build modular, interoperable applications with clearly defined interfaces.  A formal set of interfaces are being developed and standardized by the WASI Community Group (WASI-CG) under the W3C, ensuring an open and interoperable framework for building modular WebAssembly applications. 


Wasm Component Model
Wasm Component Model

Optimization for Lightweight, High-Performance

Applications Spanning the Cloud to the Edge 


Traditional approaches to cross-platform compatibility, such as virtual machines or containers, often come with significant overhead. Virtual machines require entire guest operating systems, while containers, although lighter, still carry dependencies and larger image sizes. Both options can lead to slower startup times and increased resource consumption, which are particularly problematic in environments where performance and efficiency are critical. 


WebAssembly, with its compact binary format and low memory and storage utilization, eliminates many of these challenges. Wasm modules are significantly smaller than container images, often requiring only a handful of kilobytes or megabytes of space, and execute with near-instant startup times to handle incoming tasks. This makes them ideal for ephemeral workloads in serverless platforms, where rapid scaling and cost efficiency are critical.  Meanwhile, the low footprint is also highly attractive for resource-constrained environments. 


Runtimes like Wasmtime and WAMR (WebAssembly Micro Runtime) are optimized for speed and resource efficiency. Wasmtime, designed for cloud and server-side use cases, can spin up Wasm modules in milliseconds, making it ideal for serverless computing and microservices. WAMR, built for embedded and IoT systems, has a memory footprint less than 64 KB and can be supported by a Real Time Operating System (RTOS) instead of Linux, enabling it to run on highly-constrained devices such as microcontrollers. 


Beyond its lightweight nature, WebAssembly’s design ensures near-native performance. Unlike traditional interpreted or JIT-compiled languages, Wasm is pre-compiled into an efficient binary format that’s directly executed by the runtime. This performance advantage enables Wasm to support demanding workloads such as real-time analytics, AI inference, and data processing at the edge, even on low-power hardware.  

  

Enhanced Security Through Application Sandboxing and Fine-Grained Permissions 

In today’s cybersecurity landscape, running code in secure and isolated environments is essential to protecting systems from malicious activity. WebAssembly’s architecture is inherently designed with security in mind, offering a robust sandboxing model that isolates Wasm modules from the host environment and each other. Unlike traditional application runtimes, WebAssembly enforces a strict boundary between the application and the system, ensuring that Wasm modules cannot access sensitive resources—such as the file system, network, or hardware—unless explicitly permitted. 


One of the unique security benefits of WASI is its capability-based access model. This allows developers to define granular permissions for accessing system resources, ensuring applications only have access to what they need and nothing more. For example, a Wasm module designed to process files can be explicitly granted access to a specific directory, while being completely restricted from accessing the broader file system or network. This "least privilege" approach supports robust zero trust security policies that reduce the risk of exploitation and minimize the impact of potential vulnerabilities. 


Another standout security feature is WebAssembly's deterministic execution model. Wasm modules execute in a predictable manner without side effects, meaning they cannot perform arbitrary operations such as executing native code directly. This eliminates common attack vectors such as buffer overflows, unauthorized system access, or code injection, which are prevalent in traditional native runtime environments. Furthermore, because WebAssembly binaries are compiled into a well-defined intermediate representation, they can be thoroughly audited and verified before deployment, adding an extra layer of security. 


These characteristics make WebAssembly particularly well-suited for running untrusted or third-party code in scenarios like multi-tenant cloud environments, edge deployments, or even browser-based plugins. By combining strong isolation, granular permissions, and predictable execution, WebAssembly delivers a level of security that exceeds many traditional runtime environments, offering peace of mind for developers and organizations alike. 


Enarx is a specialized WebAssembly runtime designed for secure and anonymous computing. It leverages Trusted Execution Environments (TEEs) like Intel SGX and AMD SEV to ensure strong hardware-backed isolation and runs workloads confidentially. This ensures that neither the host system nor its administrators can access the code or data being executed. This makes Enarx an ideal solution for privacy-sensitive applications, secure data processing, and multi-tenant cloud environments requiring robust security guarantees. 

  

Reduced Complexity in Multi-Language Development 

WebAssembly serves as a universal compilation target, enabling developers to write code in widely used programming languages like C/C++, Go, Rust, etc and compile it to a single, consistent runtime. Tools like the WASI SDK and the LLVM compiler infrastructure, make it seamless to compile applications into WebAssembly modules that are compatible with the WebAssembly System Interface (WASI). By leveraging LLVM, developers can target WebAssembly with minimal changes to their existing codebases, ensuring compatibility and high performance. 


Each of these languages brings distinct strengths to WebAssembly, catering to a variety of use cases. One of WebAssembly's greatest strengths is its ability to seamlessly integrate with existing C and C++ codebases, making it easier for developers to port legacy applications to modern, portable runtimes. Tools like the WASI SDK, built on the LLVM toolchain, simplify this process by allowing developers to reuse much of their existing code with minimal changes. This makes WebAssembly particularly appealing for organizations with large C/C++ codebases.  


Rust, with its focus on safety and concurrency, provides a strong alternative for applications where memory safety and reliability are critical. This is compared to C and C++ that are not memory safe programming languages. Meanwhile, Go excels in building scalable, efficient applications with its simplicity and strong concurrency model, making it a natural fit for WebAssembly in scenarios requiring lightweight, performant backends or server-side logic.  By standardizing on WebAssembly as a compilation target, developers can use a mix of   programming languages based on their strengths while ensuring their applications run consistently across runtime environments.  

 

Simplified Future-Proofing of Applications 

WebAssembly’s open standard and rapidly expanding ecosystem position it as a foundational technology capable of adapting to emerging trends in computing. Its extensibility and compatibility with modern tools make it well-suited for forward-looking organizations tackling advanced workloads, such as AI inference, edge analytics, and decentralized applications.  


The continued development of key features, including threading, garbage collection, and SIMD (Single Instruction, Multiple Data) support is further expanding WebAssembly’s applicability to more sophisticated and performance-intensive use cases. Emerging innovations like WASI-NN further enhance Wasm’s capability to enable machine learning acceleration, allowing Wasm modules to take advantage of hardware-accelerated ML libraries and devices seamlessly.  


Looking ahead, innovations like the Component Model and advancements in the WebAssembly System Interface (WASI) further establish Wasm as a universal runtime for cloud-native, edge, and IoT applications. These developments enhance interoperability and solidify Wasm’s capability as a lightweight, secure, and portable solution for addressing the next generation of computing challenges. By adopting WebAssembly today, organizations can build scalable, future-proof applications ready to meet the demands of tomorrow’s rapidly evolving technology landscape. 

  

In Conclusion 

With WebAssembly, organizations can deploy consistent application logic across the entire stack, from centralized cloud servers to decentralized edge nodes and embedded devices. This enables unified architectures that simplify development and maintenance while reducing costs. Furthermore, lightweight WebAssembly runtimes like WAMR support a variety of edge-specific workloads in resource-constrained environments. Using frameworks like WASI-NN, Wasm can interface with hardware-accelerated libraries, enabling efficient, low-latency inference for applications such as real-time video analytics, predictive maintenance, and anomaly detection at the edge. 


As WebAssembly continues to evolve, it is poised to reshape the software development ecosystem by unifying cross-platform development, enabling innovation through open standards, and delivering the performance and security required for the next generation of applications. Whether you’re creating high-performance web applications, developing cloud-based systems, or building IoT and edge computing solutions, WebAssembly is a tool worth considering. 


Check out part two of this blog for a deeper dive into the technical aspects of Wasm that make it an ideal solution for cross-platform software development. Feel free to reach out if you’d like to learn more about what we’re doing at Atym, or to talk shop about Wasm in general as it continues to revolutionize how applications are built and deployed outside of the browser. 

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