Comparison
Bun or Node.js? Speed now against stability later
The verdict
Run production services on Node.js, and use Bun today for package installs, tests, scripts and build tooling - which is where it delivers the largest wins with the smallest downside. Bun is genuinely faster: published tests put Bun.serve around 183,000 requests per second against roughly 65,000 for node:http, process start at 8 to 15 ms against 60 to 120 ms, and idle memory near 18 MB against 40 MB. What Bun does not have is an LTS program, and multi-day memory drift in long-running processes is still reported. If your service restarts often or runs short, that concern evaporates and Bun becomes a defensible production choice.
Bun 1.3 turned the runtime into a full-stack toolkit: a dev server built into Bun.serve with hot module replacement and React Fast Refresh, a unified Bun.SQL client covering Postgres, MySQL, MariaDB and SQLite, a built-in Redis client, isolated installs, dependency catalogs and a security scanner API. Node.js 26 shipped in May 2026 as Current with Temporal unflagged and Undici 8, and enters LTS in October 2026 - the same month the project moves to one major release per year, all of them LTS.
Bun vs Node.js on throughput, tooling and risk
Performance figures are published benchmark claims and depend heavily on the workload. The pattern holds up across independent tests: Bun leads on startup, install and raw HTTP throughput, and Node leads on everything to do with operating a service for years.
| Dimension | Bun 1.3 | Node.js 24 and 26 |
|---|---|---|
| HTTP throughput | Around 183,000 req/s on a hello-world server in published tests, roughly 2.8 times the Node figure. | Around 65,000 req/s on node:http. Frameworks such as Fastify or uWebSockets close much of the gap. |
| Cold start | 8 to 15 ms process start. On AWS Lambda, one comparison measured 156 ms average cold start. | 60 to 120 ms process start; 245 ms average Lambda cold start in the same comparison. |
| Memory | About 18 MB idle. At 5,000 concurrent WebSocket connections one test measured 620 MB. | About 40 MB idle, and 890 MB at the same 5,000 WebSocket connections. |
| Package install | 7 to 25 times faster than npm depending on project size. A React app typically installs in 2 to 5 seconds. | 30 to 45 seconds for the same project with npm. pnpm narrows this considerably. |
| Batteries included | Runtime, package manager, bundler, test runner, dev server, SQL and Redis clients in one binary. | Runtime plus a growing core: stable type stripping, built-in test runner, and a native watch mode. |
| Compatibility | Very high but not total. Native modules using N-API are the usual failure point, and failures are discovered at runtime. | The reference implementation. Every one of npm's roughly 2.1 million packages targets it. |
| Support model | No formal LTS. You upgrade when Bun ships, and security patching follows the same cadence. | Multi-year LTS with published end-of-life dates, which is what compliance reviews actually ask about. |
When each runtime is the right call
Choose Node.js when
- The process runs for weeks without a restart and a slow leak would page someone at 3am.
- You depend on native addons, image pipelines, gRPC bindings, or anything else built against N-API.
- A customer, auditor, or procurement process needs a named LTS version with a published support window.
- The application is already there and works. Swapping runtimes for a benchmark is not a business case.
- You want the widest set of production-tested libraries and the deepest pool of people who have debugged them.
Choose Bun when
- You are writing CLIs, codemods, monorepo scripts, or anything where a 100 ms startup tax is felt hundreds of times a day.
- CI install time is a real cost. Swapping npm for bun install is the highest-value, lowest-risk change on this page.
- You want one tool instead of five: no separate bundler, test runner, or TypeScript transform to configure.
- The service is short-lived by design - serverless functions, queue workers, request-scoped processes - so leak risk never accumulates.
- You want a single standalone executable to hand someone, which Bun compiles natively.
These are not mutually exclusive
The framing that produces the best outcome in 2026 is not "which runtime do we standardize on" but "which runtime for which job". Plenty of teams run Bun for the API layer and package management while keeping Node for legacy services and any tooling that touches native modules. That split costs almost nothing because both read package.json, both resolve from the same registry, and most application code runs unmodified on either.
If you want to evaluate Bun for a production service, the test that matters is not a benchmark, it is a soak. Run your actual service under representative load for 72 hours and watch resident memory. If the curve is flat, the main published objection to Bun in production does not apply to your workload and you can proceed with real evidence. If it climbs, you learned that in three days instead of three months.
Node's own trajectory is worth factoring in, because it has been quietly absorbing the reasons people left. Stable type stripping means running .ts files directly with no build step. Node 26 unflagged Temporal and shipped Undici 8. From Node 27 onward the release schedule simplifies to one major each April, promoted to LTS each October, with the odd and even distinction gone entirely - which removes the most common source of confusion about which version to deploy.
The one place the choice is genuinely close is serverless. Bun's 156 ms measured cold start against Node's 245 ms is a user-visible difference on infrequently hit endpoints, and short-lived functions never run long enough for stability concerns to matter. If your compute is entirely request-scoped, Bun is the runtime this comparison would pick. Details are at bun.com and nodejs.org.
Where this fits in a full stack
The backend and runtime layer covers Deno, the edge runtimes, and the frameworks that sit on top of whichever runtime you pick. If you are standing up a service rather than choosing a runtime in the abstract, the REST and backend API stack guide makes the whole set of calls.
For the command syntax across npm, pnpm and bun, including install and workspace flags, see the npm and package manager cheatsheet. Other matchups are in the comparisons index.