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Global CDN (Content Delivery Network) provider Fastly adds JavaScript in its Compute@Edge offering, further extending the flexibility in Fastly’s serverless compute environment.

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There are more developers for JavaScript than any other development language worldwide. These professionals have navigated startup latency of 250 milliseconds or more in serverless environments for years now, known as cold starts.

The cold starts delay request processing, slow down time-sensitive applications and websites.

Consequently, JavaScript developers have tried adding more functions into a single serverless deployment to compensate for the cold starts.

In turn, the larger blast radius for attacks increased their security risks. As alternative platforms also lack proper sandboxing between instances, attackers found serverless JavaScript as the perfect target.

Essentially, developers had to accept these shortcomings in safety and speed or altogether avoid using the serverless technology.


Tyler McMullen, who serves the role of a CTO at Fastly, had this to say:

When we launched Compute@Edge with a language-agnostic vision, JavaScript wasn’t one of the languages we evaluated for support, because at the time, it couldn’t compile to WebAssembly, meaning we wouldn’t have been satisfied with the security of JavaScript within our serverless compute environment. However, since we released Compute@Edge, JavaScript has been the most requested language to add, so it was top of our priority list once WebAssembly supported it. Today, we’re thrilled to open up a serverless, zero-cold start JavaScript offering with a reduced attack surface compared to similar offerings on the market. With serverless computing on the rise, we hope this motivates continued adoption of a powerful technology for businesses as they build modern digital experiences.

Fastly built Compute@Edge using WebAssembly, instead of using existing technologies for serverless computing, such as reusable containers.

WebAssembly provides for 100x faster startup times than other serverless technologies, thus resolving the cold starts issue. In turn, it resolves the speed issue for JavaScript developers.

James Governor, who serves the role of an analyst and co-founder at RedMonk, had this to say:

JavaScript is the most popular programming language today by a distance, continuing to grow and find new niches. Serverless platforms are a natural home for new JavaScript workloads. Performance and security remain key concerns, and speed is a killer feature. A reduced attack surface and no cold starts are likely to be attractive to modern web developers.

Furthermore, the Compute@Edge accounts for a unique and highly secure isolation technology. It creates and destroys a sandbox for each particular request from JavaScript compiled through WebAssembly.