So many frameworks in JavaScript -- Deno, Bun, Nuxt, Express, NextJS? What's the difference?

JavaScript has come a long way from just running inside the browser. Today, you can build everything—from CLI tools to production-grade web servers—using Node.js runtimes and modern web frameworks.

But here’s the twist: there are now so many choices—Deno, Bun, Nuxt, Express, Next.js—and each has its own personality. Let’s unpack them without the jargon.

First, What’s a Runtime?

A runtime is basically the “engine” that runs your JavaScript outside the browser. Node.js has been the default for years, but now we have Deno and Bun—two alternative engines that also run JavaScript (and TypeScript) on the server, but with new tricks and performance gains.

1. Deno – Modern, Secure Node.js Alternative

• What it is: A JavaScript/TypeScript runtime built by the original creator of Node.js, designed to fix Node’s early mistakes.
• Performance: Deno is slightly slower than Go or Rust for raw HTTP benchmarks but still much faster than Python for web servers. A simple HTTP server in Deno can handle 20k–40k requests/sec depending on your hardware—Python’s Flask struggles with ~2k–3k/sec, while Go and Rust often push past 100k+/sec.
• Advantages:
  • Secure by default (no file/network access without permission)
  • Native TypeScript support—no separate build step
  • Built-in tooling (formatter, linter, test runner)
  • URL-based imports (no node_modules bloat)
• Why use it: If you want modern defaults, tighter security, and no dependency hell. Great for greenfield projects where you can control the stack.

2. Bun – The Speed Freak

• What it is: Another Node.js alternative, built in Zig for raw speed. It’s a runtime, bundler, test runner, and package manager in one.
• Performance: Bun can cold-start a server 3–4x faster than Node.js and matches or exceeds Deno in throughput. It still won’t beat Go or Rust in extreme concurrency, but for most web apps, Bun’s speed is overkill in a good way.
• Advantages:
  • Lightning-fast package installs (no more “npm coffee breaks”)
  • Bundling & transpiling built-in
  • Drop-in Node.js compatibility for many projects
• Why use it: If you’re building serverless apps where startup time matters, or you just want your dev environment to feel instant.

3. Express – The Minimalist Backend

• What it is: The OG Node.js web framework for APIs and web servers.
• Performance: Not the fastest kid on the block, but plenty fast for most production APIs. It’s been battle-tested for over a decade.
• Advantages:
  • Huge ecosystem of middleware
  • Very easy to learn and start coding
  • Works everywhere Node.js works
• Why use it: When you want something small, flexible, and predictable. Still a great choice for REST APIs and microservices.

4. Next.js – The React Powerhouse

• What it is: A full-stack React framework that handles SSR (server-side rendering), SSG (static site generation), API routes, and optimizations.
• Performance: Not a runtime itself—it runs on Node.js, Deno, or Bun—but is highly optimized for web performance and SEO.
• Advantages:
  • Great developer experience with file-based routing
  • Automatic image optimization, caching, and prefetching
  • Full-stack in one codebase (frontend + backend APIs)
• Why use it: If you’re using React and want a production-ready app without manually wiring SSR, routing, and asset optimization.

5. Nuxt – The Vue.js Equivalent of Next.js

• What it is: A meta-framework for Vue.js that brings SSR, SSG, routing, and data fetching patterns.
• Performance: Similar to Next.js in approach—depends on the runtime underneath.
• Advantages:
  • The Vue way of building universal apps
  • Built-in performance optimizations
  • Smooth DX for Vue developers
• Why use it: If you’re in the Vue ecosystem and want SEO-friendly, high-performance apps without gluing together multiple libraries.

Speed Comparison – Requests/sec (Hello World Servers)

(These are ballpark numbers from community benchmarks; actual results vary by hardware and code structure.)

Choosing the Right Tool

• Need ultra-fast startup / low-latency? → Bun
• Want modern, secure defaults? → Deno
• Love Vue? → Nuxt
• Love React? → Next.js
• Just need a no-frills backend? → Express

💡 Takeaway:

Deno and Bun are like upgrading your car’s engine—faster, more efficient, more modern. Nuxt and Next.js are like getting a fully furnished apartment—you bring your clothes and start living. Express is the empty room—you set it up however you like.

If your app needs high performance, faster dev loops, and minimal boilerplate, picking the right one here could save you weeks of work.