Build a real-time social media API with NestJS & WebSockets featuring chat, notifications, and live user updates

What you'll learn

Understand the fundamentals of WebSockets, from TCP and HTTP handshakes to persistent connections

Build a real-time chat application using raw WebSocket APIs to gain foundational knowledge

Use Socket IO to implement custom events, rooms, and namespaces for scalable communication

Apply NestJS fundamentals (modules, services, controllers, gateways, guards) in a real-world API

Integrate JWT authentication with WebSockets for secure real-time communication

Build real-time features like messaging, conversation, post, comment

Design a scalable real-time social media backend from scratch

Structure WebSocket gateways and services cleanly within a NestJS codebase

Think from a frontend perspective to shape and deliver real-time data effectively

Requirements

Basic knowledge of jаvascript and TypeScript

Familiarity with Node.js fundamentals (functions, modules, async/await)

Some experience with HTTP APIs (e.g., building or using REST APIs)

No prior experience with WebSockets or NestJS is required — everything will be explained step by step!

Basic knowledge of MongoDB is helpful

Description

You may have heard the phrase: "To build a chat app, you need WebSockets." But have you ever stopped to ask — why?In this hands-on course, you'll learn to build a real-time social media API using NestJS and WebSockets (Socket IO) — not just by memorizing syntax, but by understanding the fundamentals behind real-time communication. We'll explore how sockets work under the hood, how data flows between client and server, and how to architect a system that can scale and respond instantly.Rather than spoon-feeding you code, this course teaches you how to read documentation, think critically, and apply these skills to your own projects. You'll gain the confidence to build and extend real-time features independently.We start with a deep dive into the fundamentals of WebSockets, from how the TCP handshake works to the HTTP upgrade process that opens a persistent WebSocket connection. You'll clearly understand what's happening behind the scenes before writing a single line of code.Next, you'll build a simple chat app using raw WebSocket APIs, giving you a solid foundation before introducing any libraries. Once you understand the basics, we'll transition into Socket IO, where you'll explore its core concepts including custom events, rooms, and namespaces — and how they simplify real-time communication.Once your WebSocket knowledge is solid, we shift gears and jump into NestJS fundamentals. You'll learn about modules, controllers, services, and guards — and then apply them to build a complete, real-time social media backendWhy This Course?This is not just another crash course. It's a practical, project-driven guide that helps you think like a backend engineer. If you're comfortable with jаvascript/TypeScript, have some Node.js or NestJS experience, and want to level up your backend skills with real-time architecture, this course is for you.By the end, you'll walk away with a complete real-time backend — ready to power your own chat app, live feed, or social platform.

Overview

Section 1: Introduction

Lecture 1 Introduction

Section 2: WebSockets Fundamental

Lecture 2 HTTP vs Websocket Protocol

Lecture 3 Build a chat app with http protocol

Lecture 4 TCP Handshake

Lecture 5 HTTP Handshake

Lecture 6 Websocket Usecase

Section 3: WebSockets in Practice

Lecture 7 Open a ws connection

Lecture 8 Send & receive data

Lecture 9 What's exactly a socket?

Lecture 10 Refactor chat app with websocket protocol

Section 4: Socket.io Library

Lecture 11 Why we need socket io library?

Lecture 12 Setup socket io

Lecture 13 Send & receive data

Lecture 14 More on send & receive data

Lecture 15 Chat App: Send message

Lecture 16 Chat App: Broadcasting

Lecture 17 Chat App: Room - part 1

Lecture 18 Chat App: Room - part 2

Lecture 19 Namespace

Lecture 20 Chat App: List users online

Section 5: NestJS Fundamental: Core Concept

Lecture 21 Explore NestJS folder structure

Lecture 22 Controller in NestJS

Lecture 23 Single responsibility principle

Lecture 24 Introduction to Provider

Lecture 25 Inversion of Control principle

Lecture 26 Apply IoC principle in NestJS

Lecture 27 Dependency Injection

Lecture 28 How IoC Container work?

Lecture 29 Look at Module

Lecture 30 Work with Module

Lecture 31 Middleware

Lecture 32 Middleware - part 2

Lecture 33 Exception

Lecture 34 Pipes

Lecture 35 Guard

Lecture 36 Interceptor

Lecture 37 Custom decorators

Lecture 38 Wrap up: Core concept

Section 6: NestJS Fundamental: Data Transfer Object (DTO)

Lecture 39 Section overview

Lecture 40 Nest CLI

Lecture 41 Setup mongodb

Lecture 42 Connect mongodb atlas

Lecture 43 Create post shema

Lecture 44 Inject repository

Lecture 45 Insert document

Lecture 46 What is a DTO?

Lecture 47 More about DTO

Lecture 48 Validation

Lecture 49 Reminder about DTO

Lecture 50 Query data

Lecture 51 Some options to reduce (hide) data

Lecture 52 Use interceptor to response DTO

Lecture 53 Transform DTO

Lecture 54 Query a data

Lecture 55 Update all fields (PUT)

Lecture 56 Update some field (PATCH)

Lecture 57 Delete document

Lecture 58 Inject another module

Lecture 59 Setup swagger UI - part 1

Lecture 60 Swagger UI - part 2

Lecture 61 Health check nestjs app

Lecture 62 Documentation for NestJS Application

Lecture 63 NestJS Lifecycle

Lecture 64 Versioning

Lecture 65 Circular dependency

Lecture 66 Wrap up

Section 7: Setup Project

Lecture 67 Setup NestJS Project

Lecture 68 Fix eslint issue

Lecture 69 Setup mongodb database

Lecture 70 Create a schema

Lecture 71 Environment variables

Lecture 72 Versionning

Section 8: Module: Authentication & Authorization

Lecture 73 Sign Up

Lecture 74 Hash password

Lecture 75 Transform DTO

Lecture 76 Generate JWT

Lecture 77 Sign In

Lecture 78 Authentication Guard

Lecture 79 Get current user

Lecture 80 Validation

Lecture 81 Authorization: role

Lecture 82 Reflector - assign value to method

Lecture 83 Role Guard

Lecture 84 The problem with role guard

Lecture 85 Resource Module

Section 9: Module: Post & Upload Media File

Lecture 86 Post schema

Lecture 87 Create a post

Lecture 88 Response post dto

Lecture 89 Get all posts & custom response dto

Lecture 90 Fix _id change after refresh

Lecture 91 Get a post

Lecture 92 Update post

Lecture 93 Remove post & custom validate mongodb _id

Lecture 94 Setup cloudinary to upload file

Lecture 95 Upload multiple files

Lecture 96 Add media file to post

Lecture 97 Delete media file

Lecture 98 Custom DTO to response url

Lecture 99 Cursor pagination

Section 10: Module: Reaction

Lecture 100 Think about reaction

Lecture 101 Reaction schema

Lecture 102 Add reaction to post

Lecture 103 Update reaction count

Lecture 104 Response reaction count dto

Lecture 105 Remove reaction

Lecture 106 Attach my reaction to post

Lecture 107 What's next?

Section 11: Module: Comment

Lecture 108 Comment schema

Lecture 109 Create comment

Lecture 110 User comment property

Lecture 111 Get comments

Lecture 112 Update comment

Lecture 113 Delete comment

Lecture 114 Delete child comment

Lecture 115 Custom response DTO

Lecture 116 Summarize

Lecture 117 Authorization

Lecture 118 Fix comment response DTO

Section 12: Module: User

Lecture 119 User schema property

Lecture 120 Get current user profile

Lecture 121 Get all users

Lecture 122 Upload avatar

Lecture 123 Upload cover photo

Section 13: Module: Friends

Lecture 124 Friend schema

Lecture 125 Send friend request

Lecture 126 Cancel friend request

Lecture 127 Accept friend request

Lecture 128 Reject friend request

Lecture 129 Get my request pending

Lecture 130 Get my friends

Lecture 131 Custom response DTO

Lecture 132 Search users

Lecture 133 Pagination users

Section 14: Module: Conversation

Lecture 134 Understand conversation & message

Lecture 135 Conversation & Message schema

Lecture 136 Create private conversation

Lecture 137 Create group conversation

Lecture 138 Get all conversations

Lecture 139 Pagination - part 1

Lecture 140 Pagination - part 2

Lecture 141 Get conversation

Lecture 142 Update conversation

Lecture 143 Add participant to group chat

Lecture 144 Remove participant from group chat

Lecture 145 Remove conversation

Section 15: Module: Message

Lecture 146 Send message

Lecture 147 Get all messages in conversation

Lecture 148 Pagination

Lecture 149 Update message

Lecture 150 Delete message

Lecture 151 Mark as seen message

Section 16: Module: WebSocket Gateway - Handle Real-Time

Lecture 152 Understand websocket gateway

Lecture 153 Think how to send socket data for message

Lecture 154 Handle update message

Lecture 155 Handle delete message

Lecture 156 Mark as seen message

Lecture 157 Post Gateway

Lecture 158 Handle post created

Lecture 159 Handle upload post media

Lecture 160 Handle post update

Lecture 161 Handle post delete

Lecture 162 Handle add reaction

Lecture 163 Handle remove reaction

Lecture 164 What's next?

Lecture 165 Comment Gateway - create

Lecture 166 Handle update comment

Lecture 167 Handle delete comment

Lecture 168 Friend Gateway

Lecture 169 Handle send friend request

Lecture 170 Handle accept friend request

Lecture 171 Handle reject friend request

Lecture 172 Handle cancel friend request

Section 17: Module: Notification

Lecture 173 Notification schema

Lecture 174 Create notification

Lecture 175 Get all notifications

Lecture 176 Pagination

Lecture 177 Mark as read

Lecture 178 Notification gateway - real time for send notification

Section 18: Post Privacy

Lecture 179 Let's handle privacy

Section 19: What's next

Lecture 180 You have learned a lot

Lecture 181 Keep learning

Intermediate Node.js developers who want to add real-time capabilities to their applications,Backend developers looking to deepen their understanding of WebSockets and NestJS,Frontend developers who are familiar with real-time communication and want to understand how it works on the backend,Full-stack developers looking to expand their skills in building real-time APIs,Developers who are eager to build social apps, chat applications, live notifications.,Anyone interested in learning how to create scalable, interactive, and responsive backend systems using NestJS and WebSockets