Node.js has a set of core modules that are part of the platform and come with the Node.js installation.

ModuleName          Description
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assert                provides a set of assertion functions useful for testing
*buffer                provides the ability to handle buffers containing binary data
*child_process        provides the ability to spawn child processes
*console            provides a simple debugging console
*cluster            allows to split a Node.js process into multiple workers to take advantage of multi-core systems
*crypto                provides cryptographic functionality
dgram                provides an implementation of UDP Datagram sockets
*dns                provides name resolution and DNS lookups
*events                provides an API for managing events
*fs                    provides an API for interacting with the file system
*http               provides an HTTP client/server implementation
*http2              provides an HTTP/2 client/server implementation
*https              provides an HTTPS client/server implementation
net                    provides an asynchronous network API
os                    provides operating system-related utility methods and properties
*path                provides utilities for working with file and directory paths
perf_hooks            to enable the collection of performance metrics
process                provides information about, and control over, the current Node.js process
querystring            provides utilities for parsing and formatting URL query strings
readline            provides an interface for reading data from a Readable stream
*repl                provides a Read-Eval-Print-Loop (REPL) implementation that is available both as a standalone program or includible in other applications
*stream                an abstract interface for working with streaming data
string_decoder        provides an API for decoding Buffer objects into strings
timers                provide functions to schedule functions to be called at some future period of time
tls                    provides an implementation of the Transport Layer Security (TLS) and Secure Socket Layer (SSL) protocols
tty                    provides functionality used to perform I/O operations in a text terminal
url                    provides utilities for URL resolution and parsing
util                supports the needs of Node.js internal APIs, useful for application and module developers as well
*v8                    exposes APIs that are specific to the version of V8 built into the Node.js binary
*vm                    enables compiling and running code within V8 Virtual Machine contexts
wasi                provides an implementation of the WebAssembly System Interface specification
*worker                enables the use of threads that execute JavaScript in parallel
zlib                provides compression functionality