Node.Js vs Deno vs Bun: Which Server-Side Runtime is Best?

We are diving deep into three powerful JavaScript runtimes. If you immediately thought Node.js, you're not alone. Deno and Bun are changing the game, and you'd be pleasantly surprised. Let's take a look.

Without bias, Node.js continues to do the work it is designed for, and it does so efficiently. It remains the most widely used JavaScript runtime outside the browser. Yes, it's powerful. Many large corporations rely on it, and they will likely continue to do so for many years to come.

Node.js was introduced in 2009 by Ryan Dahl and quickly gained popularity for running JavaScript outside the browser. It was built on Google Chrome's V8 engine (the same engine Chrome uses to compile JavaScript) and brought asynchronous, event-driven programming to the server-side. However, over time, certain design decisions, such as the use of CommonJS modules (Node.js doesn’t fully support ES Modules by default, though there is an optional opt-in), and the lack of built-in security, began to show their age. These limitations eventually led to the birth of Deno.

Why Deno Was Created

Ryan Dahl, the creator of both Node.js and Deno (surprise, surprise), explicitly cited security flaws in Node.js as one of his major regrets when reflecting on its design. In Node.js, scripts have unrestricted access to the file system and network by default, which can lead to disaster if not carefully managed. Deno was designed by Ryan to fix this problem by introducing a "secure-by-default" model, where permissions must be explicitly granted for file, network, or environment access.

Beyond its "secure-by-default" model, Deno introduces several improvements that make it a compelling alternative to Node.js. It comes with built-in TypeScript support, eliminating the need for external tooling or configuration. Deno also embraces modern JavaScript standards by using ES Modules natively, avoiding the legacy CommonJS system that Node.js still relies on. Its module system is streamlined, using URLs to import dependencies directly, which removes the need for a centralised package manager like NPM—it might actually feel unusual to work on a project not dependent on NPM. It can feel like working solo, without the familiar support structure for handling internal needs. Additionally, Deno includes built-in tools such as a dependency inspector and code formatter, reducing reliance on third-party utilities and minimising overhead, which can contribute to better performance. Nonetheless, Node.js still holds significant advantages in terms of ecosystem maturity, production readiness, and community support. Its vast NPM ecosystem and compatibility with a wide range of existing tools and libraries make it a more practical choice for many developers. In contrast, working with Deno can introduce friction when integrating with legacy systems or popular packages, making Node.js the more convenient and battle-tested option in many real-world scenarios.

Let's look at the performance benchmark for Node.js and Deno for a minute, shall we? Deno shows notable improvements over Node.js in several areas.Thanks to its Rust-based architecture and modern design (Node.js, built on Chrome’s V8 engine, was originally designed for the browser), Deno boasts faster startup times and higher HTTP throughput. Benchmarks indicate that Deno can handle more requests per second than Node.js, making it a strong candidate for high-performance applications. It also reads files slightly faster and uses memory more efficiently, partly due to its built-in tooling that reduces third-party overhead. Node.js, while slightly behind in raw speed, remains highly stable and optimized for production environments. Its performance is consistent and reliable, especially in large-scale systems where compatibility and legacy support are critical. Overall, Deno edges out Node.js in speed and efficiency, but Node.js still holds its ground with proven scalability and robustness in enterprise-grade

But what if there’s a runtime that’s even faster than both Node.js and Deno? Enter Bun.

Bun: The New Challenger

Bun is quite recent, as it turns out, only a few years old. It is a JavaScript runtime that emerged as a response to the performance and tooling limitations of existing runtimes, including Node.js and Deno. Created by Jarred Sumner and officially released by his company Oven in September 2021, Bun was born out of frustration with the speed and complexity of Node.js, especially during the development of a Next.js project. Unlike Node.js and Deno, which are built on Google's V8 engine, which in turn is built on C++, Bun uses JavaScriptCore, the engine behind Safari, and is written in Zig, a low-level programming language known for performance and safety.

Side Note on Zig:

Zig is a low-level programming language focused on performance, safety, and simplicity. It offers manual memory management, no hidden control flow, and compile-time code execution, making it ideal for building fast, predictable systems like Bun.