Node.js 20 Released: The 'Iron' LTS Line and a Permission Model

Node.js 20 was first released on April 17, 2023 under the codename 'Iron'. Beyond its LTS status, it is notable for introducing an experimental permission model, an early step toward giving developers finer-grained control over what a Node.js process is allowed to do.

The experimental permission model

Node.js 20 added an experimental permission model that lets developers restrict access to resources such as the file system, child processes and worker threads at runtime. The goal is to reduce the blast radius if a dependency or piece of code behaves unexpectedly, by making the runtime deny operations that were not explicitly permitted. Because it was introduced as experimental, teams should treat it as a feature to evaluate rather than a finished security boundary, and follow its evolution in later releases.

A built-in test runner

The release also stabilised aspects of the built-in test runner, giving developers a way to write and run tests without immediately reaching for a third-party framework. For small projects and libraries, a runtime-provided test runner lowers the barrier to having tests at all, though larger projects may still prefer the richer features of dedicated testing tools.

LTS status

As an even-numbered major, Node.js 20 moved into Active LTS, giving it a long support window suitable for production. It became the recommended base for many teams during its Active LTS period, before newer lines such as Node.js 22 and 24 took over that role.

Looking back

Node.js 20 illustrates how the runtime has steadily absorbed capabilities that once required external tooling, from testing to, increasingly, security controls. For teams maintaining older applications, it also serves as a reminder to track LTS end-of-life dates and plan upgrades to a newer supported line before support runs out.

Related on Skillo

See also: Node.js 22, the following 'Jod' LTS line.

Sources

• Node.js Releases (official)

Published date reflects the original event date (2023-04-17). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.