Node.js, Deno, and Bun: A Comprehensive Comparison of JavaScript Runtimes
Explore a detailed comparison of Node.js, Deno, and Bun, examining their performance, dependency management, tooling, security, and more to help you choose the best runtime for your next JavaScript project.
Node.js was the dominant JavaScript runtime for server-side development for a long time. However, the JavaScript ecosystem has since evolved, and new competitors have emerged to challenge Node.js's position.
In recent years, Deno and Bun have gained significant attention as notable alternatives, each offering unique features and advantages. Their rise has prompted many to consider whether it's time to transition from Node.js to either Bun or Deno.
This article provides a comprehensive comparison of Node.js, Deno, and Bun, aiming to guide you in making an informed choice for your next project.
What is Node.js?
Node.js is an open-source runtime environment built on Google’s V8 JavaScript engine. Released in 2009, it is one of the most mature JavaScript runtimes. Node.js's extensive ecosystem is powered by npm, one of the most comprehensive package registries available.
What is Deno?
Deno is an open-source runtime created by the original developer of Node.js to address various issues identified in Node.js. It was written in Rust and also uses the V8 engine. Deno supports loading dependencies via URLs, whether local or remote. It features built-in TypeScript support and has continuously worked towards better compatibility with Node.js over time.
What is Bun?
Bun is a new open-source runtime for JavaScript, released in 2021. It prioritizes performance and developer experience, utilizing WebKit's JavaScriptCore instead of the V8 engine like Node.js and Deno. Written in Zig, Bun aims to be a faster, drop-in replacement for Node.js. It includes features such as built-in TypeScript support and comes with tools for testing and creating executables, among others.
Runtime Comparison: Node.js, Deno, and Bun
Before diving into a detailed comparison of features, the table below provides an overview and summary of how Node.js, Deno, and Bun stack up across key categories.
| Feature | Node.js | Deno | Bun |
|---|---|---|---|
| Performance | Good | Very Good | Excellent |
| Dependency management | Excellent | Good (uses URLs, JSR, and deno.json) | Excellent |
| Tooling | Very Good (some experimental) | Excellent | Very Good (advanced built-in tools, lacks a REPL) |
| Built-in TypeScript support | Good (experimental) | Excellent | Excellent |
| Built-in data storage | Good (experimental SQLite) | None | Excellent (SQLite) |
| Security | Good (experimental) | Excellent | Limited (limited security features) |
| Support and community | Excellent | Good (growing steadily) | Good (small but rapidly expanding) |
| Adherence to web platform APIs | Very Good | Excellent | Excellent |
| Deployment options | Excellent | Good (Deno Deploy available) | Limited (no official deployment options yet) |
| Runtime interoperability | Very Good | Very Good (growing Node.js compatibility, supports Deno modules) | Excellent |
Performance
Performance is a critical factor when assessing the efficiency and responsiveness of an application. Bun has been heavily marketed for its speed, making performance a significant selling point at its release.
To evaluate whether Bun’s performance claims hold up, benchmarks were run based on the Bun HTTP Framework Benchmark, focusing on Express. The tests measured average throughput, including handling simple GET requests, extracting path parameters, and parsing JSON bodies.
Here are the benchmark results:
| Framework | Runtime | Average | Ping | Query |
|---|---|---|---|---|
| express | bun | 52,479.34 | 58,955.77 | 50,583.29 |
| express | deno | 22,286.51 | 23,318.99 | 22,414.20 |
| express | node | 13,254.55 | 16,821.80 | 16,250.99 |
Bun clearly outperforms both Deno and Node.js, handling over 52,000 requests per second. This confirms Bun’s position as the fastest runtime when using Express.
Deno also delivers solid performance, averaging 22,286.51 requests per second, but falls behind Bun in raw speed.
Node.js, while dependable, lags significantly, managing only 13,254.55 requests per second on average, positioning it as the slowest of the three in these benchmarks.
In terms of raw speed and efficiency, Bun takes the clear lead.
Dependency Management
This section examines the differences in dependency management among Node.js, Deno, and Bun.
Below is a comparison table that highlights how each runtime handles dependencies:
| Feature | Node.js | Deno | Bun |
|---|---|---|---|
| Package manager | npm | No dedicated package manager; uses direct URLs, import maps, and JSR | Uses a package manager compatible with Node.js |
| Registry | npm registry | JSR (JavaScript and TypeScript Registry), supports npm packages | Supports npm registry, Git, HTTP, and tarballs |
| Dependency file | package.json | Uses deno.json for Deno-specific configs, can also use package.json for Node.js projects | package.json, binary lockfile (bun.lockb) |
| Packages location | Creates a node_modules directory | Installs in a global cache by default, can use node_modules if package.json is present | Installs in node_modules directory, optimized for speed |
| Workspaces support | Supported via npm workspaces | No native workspace support; managed through module imports | Native support via workspaces in package.json |
| Versioning | Semantic versioning via package.json | Versioning via URLs, import maps, or JSR, with lockfile support | Semantic versioning, binary lockfile for speed |
| Security | Runs postinstall scripts by default | Secure by default, fewer postinstall risks, with lockfile integrity checks | Limits postinstall scripts, uses privilegedDependencies field |
| CommonJS support | Supports both CommonJS and ES modules, but compatibility issues can arise | Full support (Deno 2 now supports CommonJS) | Full support (both CommonJS and ES modules, with improved handling) |
| ES module support | Requires .mjs extension, setting module type in package.json, and command line flags | Full support | Full support |
Node.js relies on npm for managing packages. The npm ecosystem revolves around the package.json file, which lists dependencies and scripts that define a project’s structure. Dependencies are installed into a node_modules directory. Node.js supports both CommonJS and ES modules, but transitioning to ES modules has traditionally been challenging, often requiring flags, adjustments to package.json, or command line configurations for full compatibility.
Deno takes a different approach to dependency management by eliminating the need for a package.json file; instead, it uses direct URL imports and supports import maps for organizing dependencies. Deno is ES module-first and initially did not support CommonJS modules to avoid the complexity of managing multiple module systems. However, with the release of Deno 2, it added CommonJS support, significantly enhancing compatibility with the Node.js ecosystem.
Bun uses a package.json file like Node.js but enhances the process with a binary lockfile (bun.lockb) for faster dependency resolution. While Bun is ES module-first, it also offers robust support for CommonJS, treating it as a first-class citizen. This dual compatibility simplifies working with both modern ES modules and the vast ecosystem of existing CommonJS packages, without the complex configurations often required in Node.js. Bun also supports downloading packages from the npm registry, Git, HTTP, and tarballs, offering flexibility while ensuring efficient package management, all while maintaining performance and security.
Each runtime has its own approach to handling dependencies, and there isn't a clear winner overall. However, Bun stands out by making it easier to work with both ES modules and CommonJS modules, and by allowing packages to be downloaded from a variety of sources, including npm, Git, HTTP, and tarballs.
Tooling
In this section, we'll compare the tooling available in Deno, Bun, and Node.js. Having robust built-in tools can significantly reduce the need to download additional dependencies, helping you get started more quickly.
Here’s how they compare:
| Feature | Node.js | Deno | Bun |
|---|---|---|---|
| REPL | Full Support | Full Support | Not Supported |
| Formatter | Not Supported | Full Support | Not Supported |
| Linter | Not Supported | Full Support | Not Supported |
| Test runner | Full Support | Full Support | Full Support |
| Executables | Partial Support | Full Support | Full Support |
| Debugger | Full Support | Full Support | Full Support |
Deno leads the pack regarding built-in tooling, offering a REPL, test runner, easy executable creation, and debugger without needing third-party packages. Additionally, Deno includes a built-in linter and formatter, providing a complete development environment out of the box.
Node.js follows closely behind with built-in support for a REPL, test runner, executable creation, and debugger. However, it lacks Deno's built-in linter and formatter, requiring reliance on external tools for those functionalities.
Bun, while promising, falls short in this comparison. It offers a test runner, the ability to create executables, and a debugger but lacks a REPL, which is helpful for quick experimentation. Additionally, it doesn’t include a built-in linter or formatter, which are standard features in Deno.
For a more comprehensive development experience, Deno and Node.js are the best options, with Deno taking the lead due to its all-in-one toolset.
Built-in TypeScript Support
The growing adoption of TypeScript in modern web development has significantly changed how JavaScript runtimes approach built-in language support. Traditionally, developers had to configure TypeScript manually. However, newer runtimes like Deno and Bun have introduced more seamless TypeScript integration.
Here’s a comparison of how the major JavaScript runtimes handle TypeScript:
| Runtime | TypeScript first-class support | Runtime type checking |
|---|---|---|
| Node.js | Partial Support (experimental) | Not Supported |
| Deno | Full Support | Not Supported |
| Bun | Full Support | Not Supported |
Deno and Bun lead the way with first-class support for TypeScript. Both runtimes automatically transpile TypeScript files to JavaScript and execute them without needing external tools or configurations. Bun simplifies the setup further by providing a default TypeScript configuration, while Deno’s REPL also supports TypeScript, making it easy to start experimenting.
Node.js has made progress with its experimental TypeScript support. It requires using the --experimental-strip-types flag, which instructs Node.js to strip type annotations from .ts files and run them directly. However, this support is limited, handling only inline type annotations and lacking comprehensive TypeScript feature support, such as enums or namespaces. It also requires explicitly using the type keyword for type imports.
If you want to quickly and efficiently start using TypeScript, Deno and Bun offer the best experiences with minimal setup. While Node.js is making strides, its experimental support still needs to catch up to the more integrated approaches found in Deno and Bun.
It's important to note that across all runtimes, there is no built-in runtime type checking. You still need to use tools like tsc or configure your IDE for effective type checking during development.
Security
Security is critical to any runtime environment and essential for protecting applications and data. Here’s how Node.js, Deno, and Bun compare in terms of security features:
| Feature | Node.js (v20+) | Deno | Bun |
|---|---|---|---|
| Permissions model for sensitive APIs | Partial Support (experimental) | Full Support | Not Supported |
| Default sandbox environment | Not Supported | Full Support | Not Supported |
| Explicit permissions for file system access | Not Supported | Full Support | Not Supported |
| Explicit permissions for network access | Not Supported | Full Support | Not Supported |
| Subprocess security | Not Supported | Potential Risk (with --allow-run) | Not Supported |
| Runtime permission requests | Not Supported | Full Support | Not Supported |
| Security audit plans | Full Support (via tools like Snyk) | Full Support (built-in) | Potential Risk (planned) |
Deno was built with security as a top priority, featuring a comprehensive permissions model, default sandboxing, and runtime permission requests, making it the most secure runtime for JavaScript out of the box.
Node.js, as the most established runtime, offers robust security tools and has introduced an experimental permissions model in version 20. However, it lacks some of the out-of-the-box security features found in newer runtimes like Deno.
Bun is still developing its security features and lacks a permissions model and sandboxing. While future security audits are planned, it currently falls behind Node.js and Deno regarding security.
Regarding security, Deno is the most secure runtime by default because it can enforce strict permissions for accessing the file system, network, and other sensitive APIs.
Support and Community
A large and active community is a significant factor when choosing a runtime. It provides abundant resources and tools, which can significantly boost productivity and problem-solving capabilities.
Here’s an overview of community support, resources, and adoption rates for each runtime:
| Runtime | Community size & activity | Resources & ecosystem | Adoption rate & ecosystem maturity |
|---|---|---|---|
| Node.js | Extensive, with millions of developers worldwide | Over two million packages available via npm | Dominant and a well-established, stable choice |
| Deno | Smaller but steadily growing community | Continuously expanding resources, with JSR hosting around four thousand packages | Gaining traction and still in the process of maturing |
| Bun | Small yet rapidly expanding community | Taps into millions of existing packages on npm | Not yet fully mature, but quickly advancing with strong backing |
Node.js offers unparalleled support and community, thanks to its long-standing presence and extensive ecosystem. With millions of developers and plenty of packages available through npm, its maturity and widespread adoption across industries make it a reliable choice for almost any project.
Deno is gradually catching up, particularly appealing to developers who prioritize TypeScript and modern web standards. However, it hasn't yet reached the level of community growth and maturity that Node.js has enjoyed over the past decade. While Deno is making strides, it doesn't yet offer the same breadth of resources as Node.js.
Bun, though newer, is rapidly gaining traction due to its focus on performance and compatibility with Node.js. This allows Bun to leverage existing npm packages while pushing the boundaries of what's possible in a modern JavaScript runtime. However, Bun is still less mature than Node.js, lacking features like a REPL, and it has more work to do to become fully stable and reliable for large-scale use.
Adherence to Web Platform APIs
Web platform APIs ensure consistency and interoperability across different runtime environments. Support for these APIs allows developers to write portable code with browser-like functionality in server-side contexts.
| Web API | Node.js | Deno | Bun |
|---|---|---|---|
| Fetch API | Full Support | Full Support | Full Support |
URL (URLSearchParams) | Full Support | Full Support | Full Support |
| Web workers | Full Support | Full Support | Full Support |
| Streams | Full Support | Full Support | Full Support |
| Blob | Full Support | Full Support | Full Support |
| WebSockets | Full Support (via ws module or native WebSocket) | Full Support | Full Support |
| Encoding and decoding | Full Support (Buffer, TextEncoder, TextDecoder) | Full Support (atob, btoa, TextEncoder, TextDecoder) | Full Support (atob, btoa, TextEncoder, TextDecoder) |
| Crypto | Full Support | Full Support | Full Support |
| Microtasks | Full Support (queueMicrotask) | Full Support (queueMicrotask) | Full Support (queueMicrotask) |
reportError() global function | Not Supported | Full Support | Full Support |
| User interaction | Not Supported (no alert, confirm, prompt) | Full Support (alert, confirm, prompt) | Full Support (alert, confirm, prompt) |
| Realms | Not Supported | Not Supported | Full Support (supported via ShadowRealm) |
Deno and Bun are designed with strong web compatibility, offering extensive support for web APIs that closely mimic browser environments on the server.
When Node.js was first introduced, most web platform APIs were not yet standardized, but significant strides have since been made in adopting these APIs.
All three runtimes—Node.js, Deno, and Bun—offer good support for web platform APIs, making them solid choices depending on your specific needs. If web platform API compatibility is a key factor, any of these runtimes will serve you well.
Built-in Data Storage
Having built-in data storage within a runtime can be incredibly valuable for quick setups, prototyping, and applications requiring lightweight, embedded databases. This feature also reduces dependency management and can enhance performance due to native integration.
| Runtime | Built-in storage | Type |
|---|---|---|
| Node.js | Full Support | SQLite |
| Deno | Not Supported | N/A |
| Bun | Full Support | SQLite |
Node.js includes an experimental SQLite driver available under node:sqlite, allowing you to work with an embedded SQLite database natively:
import { DatabaseSync } from "node:sqlite";
const db = new DatabaseSync(":memory:");
const query = db.prepare("SELECT 'Hello world' AS message");
const result = query.get();
console.log(result); // => { message: 'Hello world' }
Bun provides built-in support for SQLite through the bun:sqlite module. It includes features like prepared statements and transactions, and it claims to be faster than better-sqlite3, making it one of the fastest options for SQLite in JavaScript:
import { Database } from "bun:sqlite";
{
using db = new Database("mydb.sqlite");
using query = db.query("select 'Hello world' as message;");
console.log(query.get()); // => { message: "Hello world" }
}
Deno, on the other hand, does not include built-in traditional database support. To use a database with Deno, you must install external packages for specific databases like MySQL, PostgreSQL, or others.
For native, built-in relational data storage, Bun and Node.js stand out as the best options, each offering robust SQLite support directly within the runtime.
Deployment Options and Project Backing
In this section, we'll explore the deployment options available for each runtime and understand the backing behind these projects, giving you a clearer picture of their support and maturity.
Here’s how each runtime stacks up:
| Runtime | Deployment options | Funding source |
|---|---|---|
| Node.js | No official deployment service, but widely supported across all major cloud providers | Open-source, backed by the OpenJS Foundation and a broad community |
| Deno | Offers Deno Deploy as an official service | Venture capital-funded, led by Deno Company Inc. |
| Bun | No official deployment options yet | Venture capital-funded, developed by Oven |
Node.js, primarily driven by contributions from a wide range of developers and supported by the OpenJS Foundation, benefits from widespread deployment support across all major cloud providers. While it doesn’t offer its own deployment service, the extensive support makes it easy to deploy Node.js applications in virtually any environment.
Deno, though newer, is expanding its deployment options with Deno Deploy as its flagship service. While Deno can also be deployed on other services, the support isn’t as extensive as Node.js. However, Deno Deploy provides a native solution if you want to leverage Deno’s ecosystem.
Bun currently lacks an official deployment service and doesn’t yet enjoy widespread support across cloud providers. However, as a venture-funded project developed by Oven, it is likely that deployment solutions will emerge in the future. Bun’s deployment options are now more limited than Deno and Node.js.
In terms of deployment, Node.js is the clear winner, as it can be easily deployed in most environments and offers the widest range of options.
Runtime Interoperability
Interoperability is a useful consideration when choosing a JavaScript runtime, especially for newer options like Deno and Bun, which may have a limited ecosystem compared to Node.js. The ability to use libraries and tools across runtimes enhances flexibility and reduces adoption barriers.
Here's a quick comparison:
| Feature | Node.js | Deno (most, but not all) | Bun |
|---|---|---|---|
| Native package format | Full Support | Full Support | Full Support |
| Can use npm packages | Full Support | Full Support | Full Support |
| Can use Deno modules | Not Supported | Full Support | Not Supported |
package.json support | Full Support | Full Support | Full Support |
node_modules support | Full Support | Not Supported (uses import maps) | Full Support |
| Node.js built-in APIs | Full Support | Partial Support | Partial Support |
Bun is the most interoperable runtime, designed to be a drop-in replacement for Node.js. It can read package.json, supports node_modules, and offers high Node.js API compatibility, making it easy for developers to migrate or experiment while keeping access to the npm ecosystem.
import express from "express";
const app = express();
const port = 8080;
app.get("/", (req, res) => {
res.send("Hello World!");
});
app.listen(port, () => {
console.log(`Listening on port ${port}...`);
});
Deno has made significant progress in Node.js compatibility, now supporting npm packages and package.json through a compatibility mode. While its use of import maps instead of node_modules and partial Node.js API compatibility may require adjustments when porting applications:
import express from "npm:express@4.18.2";
const app = express();
const port = 8080;
app.get("/", (req, res) => {
res.send("Hello World!");
});
app.listen(port, () => {
console.log(`Listening on port ${port}...`);
});
Node.js, as the established runtime, doesn’t prioritize compatibility with Deno or Bun-specific features. Instead, it leverages its vast ecosystem and implements interesting features natively.
Bun excels in interoperability with its strong Node.js compatibility, followed by Deno. Node.js doesn’t require extensive interoperability since it already includes most of the features it needs within its ecosystem.
When to Use Node.js, Deno, or Bun
Having explored various features and factors, choosing the right runtime for your project involves carefully weighing the strengths and limitations of each option.
If you're already using Node.js and wondering whether it's worth switching, it's generally not necessary. Node.js is constantly evolving, incorporating features from Bun and Deno, such as native TypeScript support, a built-in test runner, an embedded database, and a permissions model. Many features currently exclusive to Bun or Deno will likely be available in Node.js in the future. Additionally, Node.js is more mature, with a rich ecosystem of tools, libraries, and community support, making it a reliable and well-established choice.
However, if you're interested in experimenting with new tools, speed, Bun and Deno present compelling alternatives. They each offer unique advantages, like Deno’s REPL with built-in TypeScript support and its robust runtime permissions for enhanced security. Bun, on the other hand, excels in speed. Additionally, both Bun and Deno avoid the CommonJS and ES module compatibility issues that Node.js has struggled with. Still, in my opinion, these features alone don’t provide enough reason to switch from the more mature and well-supported Node.js.
Final Thoughts
This article has explored the features of Node.js, Deno, and Bun to help you assess which runtime may be best for your project. Hopefully, you now understand their differences, strengths, and weaknesses and can make an informed choice. Once you've decided on the right tool, you can dive deeper by exploring their respective documentation.