Node.js overview

As an asynchronous event-driven JavaScript runtime, Node.js is designed to build scalable network applications.

Node.js is similar in design to, and influenced by, systems like Ruby's Event Machine and Python's Twisted. Node.js takes the event model a bit further. It presents an event loop as a runtime construct instead of as a library. In other systems, there is always a blocking call to start the event-loop. Typically, behavior is defined through callbacks at the beginning of a script, and at the end a server is started through a blocking call like EventMachine::run(). In Node.js, there is no such start-the-event-loop call. Node.js simply enters the event loop after executing the input script. Node.js exits the event loop when there are no more callbacks to perform. This behavior is like browser JavaScript - the event loop is hidden from the user.

HTTP is a first-class citizen in Node.js, designed with streaming and low latency in mind. This makes Nodejs well suited for the foundation of a web library or framework.

Node.js being designed without threads doesn't mean you can't take advantage of multiple cores in your environment. Child processes can be spawned by using our child_process.fork() API, and are designed to be easy to communicate with. Built upon that same interface is the cluster module, which allows you to share sockets between processes to enable load balancing over your cores.

What’s new in version 22.20.0

Notable Changes

OpenSSL updated to 3.5.2.
For official Node.js builds, or builds using the default build configuration, Node.js now bundles **OpenSSL 3.5.2**. This update allows Node.js 22.x to be supported through to the planned End-of-Life date of **2027-04-30** as the previously bundled OpenSSL 3.0.x goes out of support in September 2026.
This change does not affect third-party builds of Node.js that link to an external OpenSSL (or OpenSSL-compatible) library.

Other Notable Changes (SEMVER-MINOR Features)

**http:** Added **Agent.agentKeepAliveTimeoutBuffer** option.
**http2:** Added support for raw header arrays in `h2Stream.respond()`.
**stream:** Added **brotli** support to **CompressionStream** and **DecompressionStream**.
**test_runner:** Supported object property mocking.
**worker:** Added **cpu profile APIs** for worker.
**sea:** Implemented `execArgvExtension`.
**sea:** Supported `execArgv` in sea config.

Other Notable Changes (General)

**crypto:** Updated root certificates to **NSS 3.114**.
**doc:** Stabilized `--disable-sigusr1`.
**doc:** Marked `path.matchesGlob` as stable.
**inspector:** Added **http2 tracking** support.

Commits and Fixes

**assert:** Capped input size in `myersDiff` to avoid `Int32Array` overflow.
**build:** Fixed getting OpenSSL version on Windows.
**build:** Fixed 'implicit-function-declaration' on OpenHarmony platform.
**build:** Used `windows-2025` runner.
**build:** Compiled bundled uvwasi conditionally.
**build:** Did not set `-mminimal-toc` with `clang`.
**child_process:** Removed unsafe array iteration.
**crypto:** Loaded system CA certificates off thread.
**deps:** Updated **uvwasi** to 0.0.23, **histogram** to 0.11.9, **googletest** to eb2d85e, and **amaro** to 1.1.2.
**deps:** Upgraded **openssl** sources to **openssl-3.5.2** and **openssl-3.5.1**.
**deps:** Fixed OpenSSL security level at 1.
**diagnostics_channel:** Revoked DEP0163.
**esm:** Added experimental support for addon modules.
**esm:** Linked modules synchronously when no async loader hooks are used.
**fs:** Fixed wrong order of file names in `cpSync` error message.
**fs:** Fixed `dereference: false` on `cpSync`.
**fs:** Fixed return value of fs APIs.
**http:** Unbroke `keepAliveTimeoutBuffer`.
**http:** Used cached '1.1' http version string.
**http2:** Reported sent headers object in client stream dcs.
**inspector:** Prevented propagation of promise hooks to `noPromise` hooks.
**lib:** Fixed `DOMException` subclass support.
**lib:** Reverted "lib: optimize writable stream buffer clearing."
**module:** Correctly detected top-level await in ambiguous contexts.
**path:** Refactored path joining logic for clarity and performance.
**path,win:** Fixed bug in `resolve` and `normalize`.
**sea:** Implemented `sea.getAssetKeys()`.
**sea:** Allowed using inspector command line flags with SEA.
**sqlite:** Handled `?NNN` parameters as positional.
**src:** Tracked BaseObjects with an efficient list.
**src:** Fixed build on NetBSD.
**src:** Fixed race on process

Node.js for Mac

Node.js overview

What’s new in version 22.20.0

Notable Changes

Other Notable Changes (SEMVER-MINOR Features)

Other Notable Changes (General)

Commits and Fixes

Node.js for Mac

Write your thoughts in our old-fashioned comment

(2 Reviews of Node.js)