Understand the inner workings of Node.js and learn how to create highly optimized applications.

Coding Beginners

Upskill your back-end technology toolset by learning the inner workings of how Node.js works under the hood.

Node.js Under the Hood is a part-time, remote course consisting of four weeks of live instruction and supplemental challenges. The course provides a comprehensive overview of Node.js and its core patterns and features, with the goal of giving you a solid understanding of how it works “under the hood” and how to most effectively use it. The content is designed for those with proficient JavaScript knowledge and/or if you already have some experience working with Node.js and want to deepen your understanding.

Program Highlights

Understand Node’s inner workings & how to use it effectively
Understand Node’s inner workings & how to use it effectively

Forming a complete mental model of how Node.js works under the hood will allow you to become a more effective developer and fully take advantage of what it has to offer.

Gain a better understanding of things you use but don’t know how it works
Gain a better understanding of things you use but don’t know how it works

We’ll go beneath the surface of features the parts of Node that are so ubiquitous they’re often taken for granted - improve your debugging skills by understanding what’s happening behind the scenes.

Get a good grasp of design patterns & why it was made that way
Get a good grasp of design patterns & why it was made that way

You’ll be able to reason about important design decisions behind Node’s architecture and grasp not just how they work, also but why they were implemented - gain a clear picture of Node’s advantages and disadvantages as a server-side programming language.

Prepare for mid or senior Software Engineering roles
Prepare for mid or senior Software Engineering roles

The strategies and concepts covered in this course are crucial for individuals preparing for a path to mid or senior-level coding roles.

Curriculum Overview

The objective of this course is to facilitate a deep understanding of how Node works by giving you a cohesive mental model of its architecture and design features, allowing you to fully take advantage of all it has to offer.

Lectures provide a conceptual framework, illustrate the purpose behind key design decisions, and shed light on the intricacies of features that are often taken for granted. Throughout the course, you'll continually reinforce your knowledge and apply what you've learned through pair-programming challenges.

Servers & HTTP

Servers & HTTP

What is Node.js? In the first section of the course, we’ll learn from first principles what makes up this technology and develop a mental model of its inner-workings. We’ll explore how it allows developers to use JavaScript - originally a browser-exclusive, client-side-only language - in conjunction with its native C/C++ code to create servers, receive/respond to client requests, and interact with OS features such as the file system.

Asynchronicity and the event loop


This section will take a more comprehensive look at the event loop Node uses to maintain its event-based, single-threaded pattern. We’ll review the event-loop cycle in-depth and gain familiarity with the several different queues used for processing and prioritizing the execution of asynchronous callbacks.

Events & Streams

Events & Streams

Node is event-driven, meaning that it follows a pattern of detecting “events” and responding to them. Here we’ll explore Node’s implementation of this pattern and the “EventEmitter” class that underlies many of its key features. We’ll see how this event pattern drives some of Node’s core functionality, such as the ability to process data in streams - and we’ll take an in-depth look at the stream module to gain a full understanding of the different types of streams (readable, writable, duplex, transform), including Node’s use of buffers and built-in handling of memory usage.

Parallel work and child processes

Parallel work & child processes

Javascript may be a single-threaded language, but the internals of the Node.js runtime are multithreaded. Node.js unlocks parallel computing through the Child Process and Worker Thread APIs and the libUV threadpool. This section will take a ‘bottom-up’ approach to instantiating the Node.js runtime from the OS Kernel and a single spawned OS Process all the way up to ‘userland’, where Javascript is executed. From these first principles, we will introduce the underlying multi-threaded nature of Node.js, followed by a series of diagrams stepping through the execution of parallel computing tasks and their myriad use cases.

The Module Pattern

The Module Pattern

One of Node’s key design features is its module pattern, which allows the developer to import isolated pieces of code as individual “modules,” both to organize one’s own codebase and to utilize open-source packages and libraries written by others. We’ll break down how this pattern works on an architectural level - from Node’s behind-the-scenes process of preparing to run our JavaScript code, to what it actually means to “require” in a file - to discover how the standard practice of splitting an application into modules affects how and where our code runs.

Node.js Frameworks

Node.js Frameworks

Node.js is typically used in conjunction with a framework (such as Express or Koa) to allow for cleaner code and provide a smoother, more efficient developer experience, but it’s important to understand what these technologies are doing for us behind the scenes - and which parts of Node they abstract away from us. In this section, we’ll identify pain points that come with using “vanilla” Node and examine strategies that popular frameworks use to solve these problems.

Upcoming Node.js Under the Hood Start Dates

Node.js Under the Hood course runs Monday - Wednesday for four consecutive weeks, with a one-hour presentation & wrap-up session on the Monday of the 5th week.

MTW 5-8pm PT / 8-11pm ET


Application deadline: Jan 31

Phone screen deadline: Feb 02

Course Tuition

Course Tuition

The tuition for Under the Hood Courses is $1,700. If you are a Codesmith Immersive graduate, your tuition is 50% off. Please reach out to our admissions team at underthehood@codesmith.io if you have any questions.


Who is Node.js Under the Hood for?

Learning is a journey

This remote course is designed for developers who want to gain a deep understanding of Node. Proficiency in Javascript is required for the course. For example, you should be familiar with Object-Oriented Javascript programming and understand Javascript Closures. If you’re looking to brush up on these concepts, Codesmith offers free weekly workshops on these topics. Previous experience with Node.js is not required, though is nice to have.

Learning is a journey

Our application process is designed to determine that students have the prerequisite knowledge to succeed in the course and we can provide additional learning resources if needed. We are looking for team players who are motivated and committed to furthering their coding expertise.

The Curriculum Team

Codesmith's team of curriculum creators are all dedicated to creating and maintaining an exceptional program curriculum, designed to teach you aspects of the technologies you can use immediately in your current role, or to help you land your next one.

Will Sentance

Will Sentance

Co-founder & CEO
Phillip Troutman

Phillip Troutman

Chief Academic Officer
Allison Pratt


Software Engineering Curriculum Developer
Ryan Trontz

Ryan Trontz

Infrastructure Engineer @ Tinder
Serge headshot

Serge Vartanov

Staff Software Engineer @ Tinder
Tayvon Wright headshot

Tayvon Wright

Backend Engineer @ Axios

Admissions Process

First Step

Online application

For those applying to Node.js Under the Hood, an advanced level of JavaScript knowledge is recommended, including a good understanding of OOP in JavaScript, closures, and asynchronous JavaScript. The application consists of one short essay question and an optional coding challenge. Please note - you must have at least a high school diploma or equivalent (i.e. GED or placement exam) to enroll in this course.

Second Step

Phone Interview

If your application is successful, you will be invited to complete a phone interview. In the interview, we will chat about your background and knowledge of the prerequisite core technologies for this course.

Third Step


After completing your phone interview, you will receive an admissions decision within 2-3 business days. If you are accepted into the program, you will receive all the details to confirm your enrollment.

Frequently Asked Questions

Why would someone want to learn Node.js?

Node is a server-side runtime environment for JavaScript, and it’s become extremely popular and commonly used across the industry. You can use many different programming languages on the backend. On the frontend, JavaScript is the only option - therefore, many development teams prefer Node since it allows applications to be written entirely in one language. This means that frontend developers can quickly and easily onboard to work on the backend as well.

What are the other courses in Codesmith’s Under the Hood Series?

The next Under the Hood course will launch this summer and will cover Data Structures and Algorithms. We’ll be adding more courses in the future, but if there are any topics you’d like us to teach - please send us an email.

What if I have other questions?

If you have more questions, please reach out to our admissions team at underthehood@codesmith.io.