About this documentation

Added in: v0.10.0

Welcome to the official API reference documentation for Node.js!

Node.js is a JavaScript runtime built on the V8 JavaScript engine.

Contributing

Report errors in this documentation in the issue tracker. See the contributing guide for directions on how to submit pull requests.

Stability index

Throughout the documentation are indications of a section's stability. Some APIs are so proven and so relied upon that they are unlikely to ever change at all. Others are brand new and experimental, or known to be hazardous.

The stability indices are as follows:

Features are marked as legacy rather than being deprecated if their use does no harm, and they are widely relied upon within the npm ecosystem. Bugs found in legacy features are unlikely to be fixed.

Use caution when making use of Experimental features, particularly within modules. Users may not be aware that experimental features are being used. Bugs or behavior changes may surprise users when Experimental API modifications occur. To avoid surprises, use of an Experimental feature may need a command-line flag. Experimental features may also emit a warning.

Stability overview

JSON output

Added in: v0.6.12

Every .html document has a corresponding .json document. This is for IDEs and other utilities that consume the documentation.

System calls and man pages

Node.js functions which wrap a system call will document that. The docs link to the corresponding man pages which describe how the system call works.

Most Unix system calls have Windows analogues. Still, behavior differences may be unavoidable.