Every few months, a new JavaScript runtime promises to "revolutionize" development. But after living through the chaos of webpack configs, the npm left-pad incident, and years of tool fatigue, developers have learned to be skeptical. So what's different about 2025?
The truth is, we're finally seeing meaningful improvements to the fundamental developer experience - not just performance numbers on synthetic benchmarks. After spending months migrating projects and building new ones with Bun, Deno, and modern Node.js, here's what actually matters when you're shipping code to real users.
The Configuration Hell Problem (And How Each Runtime Tackles It)
Node.js in 2025: Still Complex as Hell
Node.js finally added some shit that should've existed years ago. Node 22 brought TypeScript support (experimental, of course), a built-in test runner because apparently we needed our own special one, and watch mode that webpack had a decade ago. Node 22's experimental TypeScript support is broken with circular imports, stick with 20.x for now.
But setup still makes me want to throw my laptop out the window. You spend more time arguing about tooling than writing features:
- Package manager: npm (slow), yarn (which version?), pnpm (weird symlinks)?
- TypeScript setup: ts-node (sluggish), tsx (better but still meh), or build everything first?
- Testing: Jest (bloated), Vitest (trendy), Node's built-in runner (basic)?
- Bundling: webpack (config hell), Vite (opinionated), esbuild (fast but limited)?
- Linting: ESLint + Prettier configuration that takes longer than the actual feature
I counted 23 configuration files in my last "simple" Node.js API. Twenty-three! That's before I wrote a single console.log.
Bun: Opinionated and Proud of It
Bun gives you everything built-in. No webpack configs, no tsconfig bullshit, it just works:
bun init my-app
cd my-app
echo 'console.log(\"Hello from TypeScript!\");' > index.ts
bun run index.ts # Just works
No tsconfig.json required. No build step. No webpack configuration. TypeScript execution is native and instant.
The happy path with Bun is genuinely magical:
- Package management:
bun installis way faster than npm - like stupidly fast - Testing: Built-in Jest-compatible runner with no setup
- Bundling:
bun buildhandles most cases without configuration - Development: File watching and hot reloading work out of the box
But here's where Bun bites you in the ass: when it doesn't work, you're basically fucked. Need a custom webpack plugin? Too bad - Bun's bundler doesn't support it. Want specific ESLint rules? Nope, use Bun's formatter or nothing. Complex CI pipeline? Good luck debugging why your builds randomly fail on Linux but work fine on macOS.
Deno: Modern Standards, Less Bullshit
Deno 2.0 takes a different approach - less chaotic than Node, more flexible than Bun:
deno init my-app
cd my-app
deno run server.ts # TypeScript runs natively
deno fmt # Format all files
deno lint # Lint with zero config
deno test # Run tests
Deno's advantage is following web standards. Instead of Node-specific APIs, you get:
- Native fetch() instead of requiring
node-fetch - Web Crypto API for cryptography
- WebSockets that work like in browsers
- Import maps for dependency management (defined in deno.json)
The permission system adds security but also complexity. Every script needs explicit permissions:
deno run --allow-net --allow-read server.ts
It's confusing initially but pays off for security-conscious environments.
TypeScript Development: Night and Day Differences
The TypeScript experience shows how much better these new runtimes are.
Node.js: Still requires choosing between ts-node (slow), tsx (better), or building everything first. The new TypeScript support is experimental and half-broken.
Bun and Deno: TypeScript just fucking works. Copy any .ts file and run it. No bullshit compilation step, no config files, no waiting around. This transforms how you actually develop - you stop avoiding TypeScript because it's a pain in the ass.
When you can iterate on TypeScript code instantly instead of waiting for compilation, you think differently about code organization and testing. Hot reloading becomes practical for backend services, not just frontend development.
Package Management: Speed vs. Ecosystem
npm/yarn/pnpm with Node.js: Slow but everything works. The entire JavaScript ecosystem expects npm compatibility. When you need an obscure package for OAuth flows or image processing, it exists and works.
Bun's package manager: Holy shit, it's fast. Like genuinely makes npm install look like it's running on a potato. Bun claims 90% compatibility. That missing 10% will destroy your project. prisma generate worked fine, then suddenly started segfaulting after a minor version bump. Spent 6 hours tracking down why sharp was crashing - turns out Bun's binary linking is still wonky with native modules. And don't get me started on node-gyp - just assume it won't work.
Deno's URL imports: Conceptually elegant, practically complex. You can import directly from URLs:
import { serve } from \"https://deno.land/std@0.200.0/http/server.ts\";
No package.json required. But dependency management across large projects becomes unwieldy without import maps. The JSR registry offers TypeScript-first packages but has limited adoption.
Package Manager Performance:
- Bun: 10-30x faster than npm for most operations
- npm: Slow but reliable for the entire ecosystem
- pnpm/yarn: Middle ground between speed and compatibility
Testing: Built-in vs. Ecosystem
All three runtimes now include built-in test runners, but the experience varies dramatically:
Node.js test runner: Basic but functional. Good for simple unit tests, struggles with complex mocking or integration tests. Most teams still reach for Jest or Vitest.
Bun test: Jest-compatible API with instant startup. If your tests run in Jest, they'll probably run in Bun - and much faster. Perfect for TDD workflows where test startup time matters.
Deno test: Clean, TypeScript-first testing with built-in assertions. Less Jest baggage means a more modern API, but you'll miss Jest's extensive mocking capabilities for complex scenarios.
The Real Migration Considerations
From Node.js to Bun: Start with development tooling and CLI scripts. These have fewer dependencies and showcase Bun's speed advantages. Don't migrate production APIs until you've tested all your dependencies thoroughly.
From Node.js to Deno: Begin with new microservices or TypeScript-heavy projects. The npm compatibility layer in Deno 2.0 makes migration easier, but plan for some package adjustments.
Staying with Node.js: If you have complex build processes, extensive npm dependencies, or enterprise requirements, Node.js 22+ offers most modern features without migration risk. The built-in tooling improvements close many gaps with newer runtimes.
Node = configuration hell. Bun/Deno = smooth until shit breaks and you're fucked. At least with Node.js, Stack Overflow has answers when things break. With the new runtimes, you're debugging alone.
OK that's the dev stuff. Now let's talk about production where everything breaks.
You need to figure out if your team can actually operate this shit when things go wrong. Because they will go wrong.
