Bun vs Node.js

Quick verdict: Bun vs Node.js

Choose Bun if you're building a greenfield API or CLI tool, want a bundler, test runner, and package manager built in, and can tolerate occasional native-addon gaps.

Choose Node.js if you depend on native addons, deploy to managed serverless runtimes, or run a larger team where the deepest ecosystem and formal LTS support matter.

Node.js now runs TypeScript natively too (v22.18+), so "Bun has TS support, Node doesn't" is no longer the clean advantage it used to be.

When to choose Bun vs Node.js

That's the generic picture. Native addon dependencies and deployment target are what usually tip it. ↓

Bun vs Node.js: what "Bun has TypeScript, Node doesn't" misses now

Node.js added experimental TypeScript type-stripping in v22, made it available with no flag in v22.18, turned it on by default in v23.6, and ships it on by default in the current v24 LTS line. Hand Node a .ts file today and it runs, no ts-node, no tsx, no build step. That directly undercuts the "Bun runs TypeScript, Node needs a build step" line that shows up in a lot of comparison content, including earlier versions of this page.

The gap that survives is narrower but real. Node's default mode only strips erasable TypeScript syntax, so enums and namespaces, which aren't purely type-level constructs, still fail without a separate compilation step. Bun's transpiler handles the full TypeScript feature set. Neither approach type-checks your code: both Node's stripping and Bun's execution just remove or interpret types at runtime, so you still need a separate tsc pass in CI if you want actual type safety enforced.

The synthetic performance numbers deserve the same scrutiny. Bun's plain-text HTTP benchmarks post large leads, often cited as 3-4x, but those are synthetic microbenchmarks. Once a realistic application layer is involved, database queries, routing, middleware, that gap narrows dramatically in measured comparisons, down to single-digit percentages in some cases. If a benchmark number is driving your decision, check whether it's a synthetic Hello World server or something closer to your actual workload.

Native TypeScript support is now table stakes on both runtimes. The real differentiators are native-addon compatibility and deployment target support, not language features.

Bun vs Node.js: npm ecosystem compatibility in practice

Bun aims for drop-in npm compatibility and gets close: it installs and runs the large majority of pure-JavaScript packages without modification, often 10-25x faster than npm on cold caches thanks to its own installer and lockfile format. For a typical web app or API built on well-maintained JS-only dependencies, you're unlikely to hit a compatibility wall.

The gap concentrates specifically in native Node-API addons compiled with node-gyp, packages like bcrypt, sharp, or certain database drivers that ship prebuilt binary bindings targeting Node's internal ABI. These are exactly the packages covered by the production gotcha below: they can install and pass tests while still failing under real concurrency. Before adopting Bun for an existing project, audit your dependency tree specifically for native bindings rather than assuming "it installed fine" means "it's compatible."

Node.js carries no equivalent risk here by definition, its ecosystem is the one every native addon targets first. That's less a Node advantage than a reflection of it being the incumbent: the compatibility gap exists because Bun is the newer runtime catching up, not because of any inherent limitation in Bun's architecture.

Run your actual dependency list through Bun in a staging environment under realistic concurrency before trusting a clean install as proof of compatibility.

Production gotcha: what nobody tells you

Bun's native module compatibility breaks silently under load. Specifically, any npm package that shells out to a native Node-API (.node) addon compiled against Node's internal ABI, things like bcrypt, sharp, or certain database drivers, will appear to install and even pass unit tests, but will segfault or return corrupted data under concurrent request pressure in production. This is not in Bun's documentation as a hard blocker. You will discover it at 2am after three months of smooth staging runs, because your staging environment never hit the concurrency threshold that triggers the underlying memory layout mismatch.

Bun vs Node.js: migration cost and what you can hedge with

A realistic migration for a mid-sized API service takes one to two engineer-weeks, covering a native-addon audit, CI pipeline updates, and integration test validation. CommonJS interop, dynamic require() patterns, and process.env handling generate the most edge-case tickets. Migrating back from Bun to Node.js is faster, roughly two to three days, since you're moving toward the larger superset of compatibility.

Before committing to a full runtime migration, there's a lower-risk middle option: use Bun purely as a package manager while keeping Node.js as the runtime. Running bun install in CI captures most of the 10-25x speed improvement over npm on cold caches, while services still execute on Node, avoiding the native-addon and managed-serverless risk entirely. Many teams treat this as step one before deciding whether a full runtime switch is worth it.

Hiring risk is smaller than it looks either direction. Any experienced JavaScript or TypeScript engineer ramps on Bun quickly, since its API surface is intentionally Node-compatible. The real cost is that job postings, onboarding docs, and vendor integration guides all have to account for a non-default runtime, which is a documentation and process cost more than a skills gap.

If you're not sure a full migration is worth it yet, the package-manager-only approach is a reasonable way to capture some of the upside without the native-addon risk.

Common questions about Bun vs Node.js