Wasm is a compelling technology with an array of use cases up and down the tech stack—but don't let the gotchas surprise you. Here's what teams need to know before adopting WebAssembly.
WebAssembly, or Wasm, is an open standard that defines a portable binary-code format and corresponding text format for executable programs. Created and maintained by the World Wide Web Consortium (W3C), Wasm is designed to facilitate high-performance applications on web pages. It supports multiple languages, is compact and fast, is supported by every major browser, and is generally safe and secure.
However, like any standard, Wasm comes with potential roadblocks. It “offers powerful capabilities for running near-native performance code on the web, but it also brings unique challenges for organizations, especially during the adoption and integration phases,” says Max Shak, founder and CEO at Nerdigital.com, a provider of digital marketing technologies and services.
For organizations embracing Wasm, it is vital to understand the drawbacks and potential hurdles that may come with using it, as well as how to get around them. We asked developers and tech leaders what they had learned from using WebAssembly in their projects.
5 things tech teams need to know before adopting WebAssembly
- Watch out for compatibility issues
- Don’t take cross-browser performance for granted
- There will be security risks and tradeoffs
- Debugging is complex and not well-supported
- The third-party ecosystem is smaller than you think
Watch out for compatibility issues
The WebAssembly homepage notes that Wasm “is designed to maintain the versionless, feature-tested, and backwards-compatible nature of the web.” WebAssembly modules can call into and out of a JavaScript context and access browser functionality through standard web APIs. But that doesn’t mean Wasm is free of compatibility issues. “WebAssembly presents a unique challenge in terms of ensuring compatibility with existing technology stacks,” says Gary Gilkison, principal analyst at Riverbase Cloud, a provider of website enhancement services.
“In my experience with software adoption, I’ve found that careful planning and modular design can mitigate this issue,” Gilkison says. In his work with Wasm, he has focused on building flexible systems with robust API support. This allowed smoother integration and reduced potential friction with technologies such as Wasm, he says.
Also see: 11 surprising ways developers are using Wasm.
While Wasm is excellent for performance-intensive tasks, Shak says his company found it challenging to integrate seamlessly with JavaScript and the Document Object Model (DOM). “Wasm doesn’t have direct access to the DOM, meaning we had to bridge data between JavaScript and Wasm, which can introduce significant overhead and increase complexity,” he says.
To address this, Nerdigital adopted a strategic approach to decide which parts of its application needed Wasm’s high performance and left non-essential parts to JavaScript. “By segmenting tasks like image processing and data manipulation for Wasm, while leaving UI rendering and event handling to JavaScript, we found a balanced integration,” Shak says.
Don’t take cross-browser performance for granted
Another potential snag with Wasm is failing to optimize performance across browsers.
“Ensuring efficient performance while using Wasm can be tricky,” Gilkison says. “From my product management experiences, I emphasize the importance of optimizing code and conducting thorough performance tests,” Gilkison says. “Balancing performance requirements against resource loads is key to delivering a seamless user experience.”
WebAssembly “offers near-native performance, but achieving consistent speed across different browser environments remains challenging,” says Paul Kromidas, CEO and founder of Summer, a provider of services for property managers, owners, and investors.
“Some browsers handle specific optimizations better than others, which complicates creating a uniform user experience,” Kromidas says. “Addressing this requires extensive cross-browser testing, along with fallback mechanisms that maintain functionality if optimal performance isn’t achieved.
For this reason, many development teams build modular Wasm components to accommodate each browser’s unique capabilities, Kromidas says, minimizing the need for significant rewrites when discrepancies arise.
There will be security risks and tradeoffs
Wasm also comes with cybersecurity risks that might take development teams by surprise if they are not expecting them. “The power of WebAssembly’s low-level code execution can [be] a security risk if not handled properly,” Kromidas says.
“Wasm’s flexibility, while beneficial, can lack the strict security protocols seen in traditional JavaScript, making it vulnerable when running untrusted code,” Kromidas says. “One effective solution is to use sandboxed modules that restrict access to sensitive parts of a system. This approach creates a layered security framework that isolates Wasm modules, striking a balance between high performance and necessary security measures.”
The security concerns with WebAssembly “can’t be ignored,” says Steve Pogson, founder of marketing solutions provider Helm Digital. The technology executes code directly in the browser, creating potential vulnerabilities. “We address this by prioritizing secure coding practices and constant monitoring, akin to our practices in maintaining secure, SSL-compliant e-commerce sites for our clients.”
Security is both a benefit and a challenge with Wasm, Shak says. “Its sandboxed environment is fantastic for protecting applications from malicious code execution, but it also limits access to essential APIs,” he says. “For example, we found it limiting that Wasm couldn’t easily interact with APIs for local storage or network requests without routing them through JavaScript.”
Nerdigital addresses this limitation by using JavaScript as a “conduit” for external requests, creating a controlled interface that allows Wasm to interact with necessary APIs through JavaScript. “This design gives us more control over what external data is exposed to Wasm, reinforcing security while still achieving functionality,” Shak says. “Additionally, we followed strict practices for sanitizing and validating any data going in and out of the Wasm modules, ensuring that security remained a top priority.”
Debugging is complex and not well-supported
Debugging complexity and limited tooling support are additional hurdles with Wasm. “Debugging in WebAssembly is often more complex than in traditional JavaScript due to a lack of mature tools for inspection and tracing,” Kromidas says. “This makes diagnosing performance and logic issues challenging, especially for teams less familiar with Wasm’s unique architecture.”
To overcome this, many developers implement detailed logging within Wasm code and use polyfills in development environments to assist with debugging, Kromidas says. “This dual approach helps identify issues effectively, capturing valuable insights without sacrificing Wasm’s performance advantages,” he says.
The debugging and tooling landscape for Wasm “often feels less mature compared to other languages,” Gilkison says. “While consulting on SaaS projects, I’ve seen the value of incorporating community-driven resources and tools. Leveraging developer forums and gathering collective insights contributed to overcoming these tooling gaps.”
“One of the biggest challenges we faced with Wasm was the lack of mature debugging tools compared to JavaScript,” Shak says. “Wasm’s low-level nature means you’re working with a stack-based virtual machine, making error messages cryptic and difficult to interpret.”
Debugging becomes even more challenging when issues arise from cross-language compiling, as JavaScript and Wasm communicate in a binary format, Shak says. “To address this, we leaned on sourcemaps to bridge the gap between our source code and the Wasm binaries,” Shak says. “Additionally, we broke down our application into smaller, modular components, allowing us to isolate and debug each Wasm module independently, which saved us time and headaches.”
The third-party ecosystem is smaller than you think
When Wasm was first introduced, its ecosystem expanded rapidly. Over time, the support for programming languages compatible with Wasm has also grown and Wasm now supports many languages. But there remains a limited availability of libraries and frameworks that support Wasm natively, Shak says.
“While this is improving, there are still fewer options compared to JavaScript, meaning we often had to write custom code or wait for the ecosystem to mature,” Shak says. “To bridge this gap, we started by building and documenting reusable Wasm components internally, which helped streamline development.”
The open source community for Wasm is growing, Shak says. “We contributed to forums and repositories, which not only enhanced our resources but also allowed us to leverage the insights of others in the field,” he says. “Staying active in the Wasm community keeps us updated on new tools, libraries, and best practices, which accelerates the development of our Wasm-powered projects.”
WebAssembly’s potential for enhancing web performance “is undeniable, but it’s not without its challenges,” Shak says. “By taking a methodical approach to debugging, modularizing the code, strategically integrating with JavaScript, and staying vigilant about security, we were able to address the pain points of Wasm.
“As the technology and its ecosystem mature, we’re excited to see WebAssembly become an even more powerful tool for web applications, and we’re continuously refining our strategies to harness its capabilities while navigating its limitations.”
