Bun: Where It Wins and Where I Still Use Node

Bun is genuinely fast, and I use it every day. I also still deploy most client work on Node, and both of those statements are considered opinions rather than a contradiction.

Here is where I draw the line.

Where it wins clearly

Installing dependencies. bun install is dramatically faster than the alternatives. On a monorepo with three apps this is the difference between getting coffee and not.

The test runner. Fast, built in, Jest-compatible enough that migrating simple suites is mostly a find-and-replace. No separate test framework, no transform configuration, no config file explaining how to run TypeScript.

Running TypeScript directly. No build step for scripts and tooling. For the small utilities every project accumulates, this removes an entire category of setup.

Scripts and tooling generally. Anything that runs on my machine or in CI rather than serving traffic.

Where I stay on Node

Production servers for client work. Not because Bun cannot serve traffic — it can — but because the operational ecosystem around Node is deeper: more battle-tested deployment targets, more monitoring integrations, more answers when something breaks at an awkward hour.

For a project I hand to a client who will maintain it with whoever they hire next, "boring and universally supported" is a feature I am choosing deliberately.

Anything depending on native modules with complex build requirements. Compatibility is good and it is not identical, and discovering a gap during a deploy is not when you want to find out.

The pragmatic split

bun install      # yes
bun test         # yes
bun run script   # yes
node server.js   # in production, for now

That is not fence-sitting. It is using each tool where its trade-offs are favourable, and the trade-offs genuinely differ between "my laptop" and "a server a business depends on."

What would change my mind

Client-side factors mostly: hosting platforms treating it as a first-class target, and enough time in production across the ecosystem that the unusual failure modes are documented by someone other than me.

That is trending in one direction, and I expect to revisit this. Adopting a runtime for client production work is a decision to make on evidence rather than enthusiasm.

Resources

• Repo: oven-sh/bun
• Docs: bun.sh/docs
• Video walkthroughs: YouTube: Bun tutorial