Node.js has tough competition
What makes Bun so efficient?
If you've touched JavaScript in the past decade, you're probably running something on Node.js. It’s stable, mature, and deeply integrated into the web dev ecosystem.
But recently, Bun has been making a lot of noise — mostly for how fast it is. Not just “slightly faster,” but 2x to 10x faster in many workflows: server startup, package installs, bundling, test runs, and even HTTP requests.
I dug into the why. And it’s not just “newer is better.” Here’s a breakdown, from a developer who uses Node.js in production.
🔍 1. Different JS Engines: V8 vs JavaScriptCore
Node.js is built on Google’s V8 (same as Chrome). Bun is built on Apple’s JavaScriptCore (used in Safari).
V8 is incredibly optimized for long-running workloads and massive JS apps — but it’s heavier. JavaScriptCore, while leaner, shines in startup performance and smaller memory usage.
⚡ 2. Bun Owns the Whole Stack
Node.js depends on a chain of external tools for things like:
Transpiling TypeScript (tsc)
Bundling (esbuild, webpack, etc.)
Testing (Jest, Vitest)
Package management (npm, yarn, pnpm)
Bun ships all of that, built-in. One binary. No context switching. No extra processes. It handles:
Running TypeScript files
Bundling and transpiling
Serving static files
Installing packages (way faster than npm)
This tight integration means zero overhead and no glue code between tools.
-- 🧱 3. Bun Is Written in Zig — Not C++
Bun is built from scratch in Zig, a modern low-level language that gives the devs more control over memory, concurrency, and compile-time behavior.
Node.js, on the other hand, is a complex C++ codebase tied deeply to V8 and decades of ecosystem baggage.
The result?
Bun’s binary is smaller and faster. Memory usage is more predictable. Updates are leaner and faster to ship.
🧠 5. Node’s Strength Is Stability, Not Speed
Node.js is battle-tested. It’s everywhere — in big infra, cloud platforms, tooling, and a massive ecosystem. But that maturity comes with constraints:
Compatibility with CommonJS Support for older modules and build systems Long-term LTS cycles Dependency on external toolchains
Bun doesn’t have that baggage. It can make aggressive performance choices without breaking the ecosystem. That’s a huge edge — at least for now.
🧵 TL;DR Bun is faster than Node.js because:
It uses a lighter JS engine (JavaScriptCore) It integrates the whole toolchain into one binary It’s written in Zig for performance It avoids legacy compatibility concerns But Bun’s ecosystem is still growing. For teams that rely on specific npm packages, mature debugging, or cloud compatibility — Node is still the safe bet.
Still, Bun is not a toy. If you’re building new projects and want speed + simplicity, it’s absolutely worth trying.