Built-in modules

Node.js has several modules compiled into the binary. These modules are described in greater detail elsewhere in this documentation.

The built-in modules are defined within the Node.js source and are located in the lib/ folder.

Built-in modules can be identified using the node: prefix, in which case it bypasses the require cache. For instance, require('node:http') will always return the built in HTTP module, even if there is require.cache entry by that name.

Some built-in modules are always preferentially loaded if their identifier is passed to require(). For instance, require('http') will always return the built-in HTTP module, even if there is a file by that name.

The list of all the built-in modules can be retrieved from module.builtinModules. The modules being all listed without the node: prefix, except those that mandate such prefix (as explained in the next section).

When being loaded by require(), some built-in modules must be requested with the node: prefix. This requirement exists to prevent newly introduced built-in modules from having a conflict with user land packages that already have taken the name. Currently the built-in modules that requires the node: prefix are:

• node:ffi
• node:sea
• node:sqlite
• node:test
• node:test/reporters

The list of these modules is exposed in module.builtinModules, including the prefix.