Teach on Udemy

Turn what you know into an opportunity and reach millions around the world.

Learn More

Your cart is empty.

Keep shopping

NodeJS Internals and Architecture

Name: NodeJS Internals and Architecture
Rating: 4.9 (804 reviews)

Understand how Node works inside out to improve performance, efficiency and consistency of your backend applications

Created byHussein Nasser

Last updated 4/2025

English

Bulgarian [Auto],English [Auto],

What you'll learn

NodeJS Architecture
NodeJS protocols, file and socket programming internals
Optimize Node JS
Writing efficient code
Multi-threaded Node
Libuv Asynchronous IO
Node Networking
Node Streams
C++ Addons

Course content

5 sections • 44 lectures • 21h 9m total length

Introduction1:56
Welcome to Node Internals and Architecture course. If you choose this course chances that you have already use Node. This is not a course about how to get started with NodeJS, it is a course to understand everything there is about the internals of NodeJS so you can take advantage of it.
Who is this course for?3:05
This course for software engineers who use Node and want to take their understanding of this runtime to the next level. Write efficient code, optimize Node, and take advantage of Node various features to unlock potentials.
Course Data0:49
Because this course will dive into the bowls of the OS, I recommend taking my fundamentals of operating systems.
Course Outline6:58
Explore the Node.js architecture with V8 and libuv, learn about the event loop, io, dns, tcp/udp, http, tls, streams, processes and threads, and master performance optimization and debugging.
What do you need?6:22
Any OS will work, Linux or Mac machine preferred since we will use the various tooling on UNI* not available on Windows.
Node version 20-22

Node JS Architecture Intro9:29
Explore Node.js architecture by examining the JavaScript execution engine and IO within the event loop. Identify phases like timers, poll, check, and promises, and compare require vs import and packages.
Interpreted Languages and V849:01
We discuss how compiled and Interpreted languages work, and how V8 the engine behind Node can compile javascript to machine code if the function is hot.
The Event Loop24:13
This is an overview of the event loop, a critical piece of the Node runtime.
The Main Module19:38
Before anything can run, we synchronously execute all code in the main module before we event start the loop. This is called the initial phase.
Timers Phase26:10
Pending Callbacks Phase14:02
Idle, Prepare Phase18:22
Unpack the idle prepare phase in Node's event loop, revealing how libuv prepares for IO by setting up structures like epoll, with a hands-on strace demo of system calls.
Poll Phase (Updated)47:48
Explore the Node.js poll phase as this lecture details how IO events and callbacks execute, the blocking vs non-blocking distinction, and epoll-based async IO with libuv.
Check Phase23:06
Master the check phase in the Node.js event loop, which runs after the poll phase and uses setImmediate to split large callbacks, enabling deterministic, non-blocking IO and predictable output.
Close Callbacks Phase24:07
The close callbacks phase schedules and finally fires close events for sockets and connections, since closing is an io operation that takes time and may delay pending callbacks.
Process.nextTick16:45
Explore how Node's process.nextTick runs after every event loop phase, enabling deterministic microtasks, its difference from timers and setImmediate, and the danger of nested nextTick calls.
How Promises work under the hood22:43
We explain how promises, async await are callbacks behind the scenes.
Require, Import Event34:10
Understand require and import in node.js: require loads synchronously at initialization and can be conditional. Import offers asynchronous IO and returns a promise, enabling dynamic loading and error handling.
Anatomy of Node Packages32:34
When does Node terminate?20:30
Node exits when there is no code to execute. While it may appear that we don't have any code executing, Node is working behind the scenes, example is listening, accepting and reading from connections.

We will do an strace to prove that while we appear to not have any code running, Node still does.
Micro / Macro Queues0:30

Node Internals Section Intro6:41
libuv Overview8:04
Go through the libuv io phases, event loop, thread pool
Asynchronous IO in the Operating System29:34
The OS course
Inside Node Network IO43:35
In this lecture we discuss how node performs network io as a client and as a server
Inside Node File IO51:50
show that passing file descriptors are faster.
how it works
reading sync vs async ,

do strace
Inside Node HTTP1:14:03
What is really happening?
Inside Node HTTPS1:00:55
Explains how https encrypts http traffic via TLS, covering symmetric and asymmetric encryption and the TLS handshake. Illustrates certificates, chains, root authorities, and Node.js https usage with OpenSSL-generated keys.
Inside Node DNS47:59
Explore how the domain name system translates names to IP addresses, enabling load balancing and geo DNS, and examine how Node.js resolves DNS with host files and the thread pool.
Inside Node TCP48:36
Explore how node's net module implements tcp, covering the three-way handshake, segments, sequencing and acknowledgments, with flow and congestion control for reliable, ordered communication.
Inside Node UDP34:02
Inside Node Streams1:03:11
We discuss NodeJS streams
Process vs Thread1:00:37
OS course
Worker Threads51:54
Explore how node's single threaded model uses worker threads to offload cpu work into event loops. Learn to communicate via message channels and workerData to distribute tasks across threads.
Child Process and Cluster36:30
Explore Node.js child processes and cluster, comparing processes and threads and IPC. Learn how forking creates independent workers with IPC channels and how scheduling policies like round-robin distribute connections.

Optimization Section Intro13:22
Node Performance39:35
Debugging NodeJS8:06
Learn to debug Node.js with a compatible debugger, using VS Code and Chrome remote debugging via the inspect protocol. Set up a launch.json, place breakpoints, and inspect responses and variables.
Capturing Node's Traffic32:35
Request modules performance showdown22:23
doing a memory and time
C++ Add-ons39:21
Explore building and debugging a C++ add-on for node.js by wiring a two-number add function through napi, using the node API, binding files, and debug across C++ and JavaScript.
Course Summary8:38
Explore Node.js architecture with libuv, the event loop, and V8; dive into internals from file I/O and networking to TLS, streams, clustering, and performance best practices.

Requirements

Backend and Operating Systems Fundamentals

Description

My favorite thing in software engineering is the art of making it transparent.

Node is one of the most popular runtimes used on backend engineering yet I feel it is the least understood. I surely felt this way at times.

I spent months working on a course to demystify NodeJS Internals and Architecture and distilled this in this comprehensive course.

I built this course is for the engineers who can't stand working with something opaque.

They love to understand what is running behind the engine.

They enjoy tearing apart 1 the line of code into its original 1000 lines.

They question why is the output of a Node program is unpredictable.

They want to know when does the Node process exit.

They want to know why Node takes so long to start in some cases.

They appreciate how Node works on all operating systems and would like to know how it does that.

For example by understanding the internals of HTTP module, you can write a backend in Node that accepts and process more requests. Every line of code you write you would think of how and when Node will process it.

By understanding the event loop and the different stages you can tune and re-order your code to achieve best performance and even consistent result.

Ever wrote a program in Node that fails 1% of the time while succeeds 99%? Understanding Node architecture helps you make your program predicable. As opposed to adding workaround because you don't understand. We all did that.

It is all about removing blockage and letting the main loop phases “breath”. When we build software the problem is we often go against the grain. Understanding where the friction is in Node allow you to work with it as oppose to against it.

In this course I cover the following

- NodeJS Architecture

I cover the various phases in the event loop and what exactly happens in each phase, how promises are just callbacks, how and when modules are loaded and their effect on performance, Node packages anatomy and more

- Node Internals

This is where we go one layer deeper, how Node truly achieves asynchronous IO with libuv, and how each protocol in node is implemented. How concurrent node works on both user level threads and process level.

- Node Optimization and Performance

Now that we understand the internals and architecture of Node, this is where we discuss tips how to make the code runs more efficiently and more performance. And only when we exhaust all other avenues Node provides ways to extend it with C++ add-ons where JavaScript just can't no longer hold.

This course is for intermediate students who are familiar with Node and want to understand how it works. While not required, I recommend taking the fundamentals of operating system course as a prerequisite of this course.

Who this course is for:

Intermediate level software engineers who want to understand Node internals
Backend engineers who want to run Node efficiently

NodeJS Internals and Architecture

What you'll learn

Explore related topics

Course content

Introduction5 lectures • 19min

NodeJS Architecture16 lectures • 6hr 23min

Node Internals14 lectures • 10hr 18min

Optimization and performance tips7 lectures • 2hr 44min

Bonus Lectures2 lectures • 1hr 26min

Requirements

Description

Who this course is for: