Bun vs Deno vs Node.js: The JavaScript Runtime Race Explained

A runtime is the program that runs JavaScript code on a server, outside the browser. For years Node.js was the only serious choice. Two newer rivals, Bun and Deno, offered speed and extra built-in tools. In the autumn of 2026 both made news, and the news changes how a careful business should think about them.

Where each runtime stands

Node.js

Node.js remains the established option. Node.js 26 became a long-term-support release on 28 October 2026, and the official schedule has it supported until 30 April 2029. Node.js 24 is supported until April 2028. Our Node.js version guide has the full dates.

Bun

Bun is a runtime, package installer and test runner in one tool. Bun 1.4 was released on 20 August 2026, and the newest version listed on its blog as of November 2026 is 1.4.4, from 22 October. Release notes say this is the first version of Bun written in Rust instead of Zig. The announcement claims idle processor use down by up to 5 times, memory use down by up to 35 per cent and faster startup on Linux. Those are the vendor's numbers from its own tests.

On compatibility, the same post says the main Node.js modules pass about 97 per cent of Node's own tests, that tools including Next.js 16, Playwright and Vitest now work on Bun, and, in its own words, that Bun is not 100 per cent compatible with Node.js yet. It also lists breaking changes, such as stricter security checks on TLS certificates.

Deno

Deno was created by the original author of Node.js. Version 2.9 was announced on 25 June 2026. Then, on 9 October 2026, the company announced that the Deno team is joining Cloudflare. According to that post:

• Cloudflare will support the Deno runtime for one more year, with monthly bug-fix and security releases. After that year, its own development ends, though Deno will remain open source and others are invited to continue it.
• Deno Deploy, the hosting service, will run for six months and then shut down, with migration help for paying customers moving to Cloudflare Workers.
• JSR, the package registry, continues, with its infrastructure moving to Cloudflare.

Read that carefully: a project that depends on Deno Deploy has a hard deadline, and one that depends on the Deno runtime itself has a year of support promised, with an uncertain future after.

What this means for a business

A runtime is a foundation. If it is changed or abandoned, everything on top needs work. Three things matter more than speed:

• Longevity. Who maintains it in five years, and how many developers can take over your code?
• Compatibility. Do the payment, database and email libraries you rely on run on it without surprises?
• Hosting. Does your host support it as a first-class option?

On these three, Node.js is the safest. Its release dates are published years ahead, nearly every host supports it, and the largest pool of developers knows it.

When Bun or Deno could make sense

• Bun as a developer tool. Using Bun to install packages or run tests, while the live site still runs on Node.js, carries little risk and can save time. Check that the lockfile and test results match before relying on it.
• Bun in production for internal tools where an occasional compatibility problem is tolerable and a developer is on hand.
• Deno for experiments and short-lived projects, not for systems that must run for years, given the Cloudflare announcement.

Our recommendation

For payment pages, school systems, billing and anything customers depend on, stay on a Node.js LTS release. The savings from a faster runtime are small compared with the cost of an unplanned migration. Our own backends use Node.js, and we record the runtime in each project's handover notes so another developer can pick it up. We stay interested in Bun's progress and would test it on a client's staging copy before ever recommending it.

A short checklist before anyone proposes a new runtime

1. Ask what problem it solves for you, in minutes saved or rupees saved.
2. Ask which libraries in your project were tested on it.
3. Check whether your host supports it officially.
4. Ask what the exit plan is if the runtime is discontinued.
5. Run a trial on a copy with real data before any live switch.

If you want an independent view on a technology choice, contact VS Tech Builders. Our guide on how to choose a software company explains what good technical advice sounds like, and technical debt is the cost you pay when a foundation has to be replaced early.

Sources

Checked on 3 November 2026. Technology changes quickly; always confirm details with the official source before you act on them.

• Bun 1.4 — Bun
• Deno is joining Cloudflare — Deno
• Deno Blog — Deno
• Node.js Releases — Node.js

Frequently asked questions

Is Bun faster than Node.js?

Bun's own release notes claim lower processor and memory use, and faster startup, in its tests. Real results depend on your application. For most business sites, database calls and network delays dominate, so a runtime change rarely makes pages noticeably faster. Test with your real workload before switching.

Is Deno shutting down?

Not immediately. On 9 October 2026 Deno announced its team is joining Cloudflare. Cloudflare will support the runtime for one more year with monthly fixes, then development ends, and Deno will remain open source. Deno Deploy, the hosting service, will shut down after six months.

Which JavaScript runtime should my business use?

For production systems, use a supported Node.js LTS release, currently 24 or 26. It has the longest published support, the widest hosting options and the largest pool of developers. Bun or Deno can be tried for tools and experiments, but with an exit plan.

Can I run Next.js on Bun?

Bun's 1.4 release notes list Next.js 16 among tools that now work on Bun. That does not mean every feature or every plugin behaves identically. If you want to try it, test a copy of the site and compare results against Node.js before changing anything live.