Building a Chat Platform Using Spring Boot

Learn the essential process of building Observability in a microservices architecture (MSA) environment from basics to practical implementation. Through step-by-step hands-on practice, you'll master standardized data collection using OpenTelemetry, trace storage and search with Grafana Tempo, and visualization using TraceQL. You can learn the process of tracking service flows through distributed tracing, identifying bottlenecks, and analyzing the root causes of failures.

Learn the process of building data pipelines using Apache Airflow from basics to practical application. Understand Airflow's core concepts and architecture, and master advanced design patterns frequently used in practice such as dynamic DAGs, parallel processing, distributed processing, and Custom Operators through hands-on exercises. Set up a practice environment with Python and Docker, and develop practical skills to design and operate real workflows.

Learn how to design and process large-scale data architecture that handles hundreds of billions of data records using only pure SQL and MySQL's core features, together with a Toss developer who handles hundreds of billions of financial traffic transactions and a developer who started as a non-major and is now developing platforms in Pangyo.

We will develop a scalable order processing system capable of real-time event streaming using Spring Boot 3.x + Kotlin to build a Kafka cluster, leveraging PostgreSQL CDC with Debezium Connect and Apache Avro schema.

This course covers how to set up multi-module projects from scratch using Kotlin and Spring Boot. It proceeds with a hands-on approach, covering everything from the basic concepts of modularization to Gradle configuration, managing dependencies between modules, and actual application development. If you are a beginner or intermediate developer looking to learn the fundamentals and practical application of multi-modules, please refer to this course.

Kotlin mastery via virtual payment server course.

Using Spring Boot 3.x + Kotlin, we build a 3-instance cluster, and utilizing Redis Pub/Sub distributed messaging and an Nginx load balancer, develop a scalable WebSocket real-time chat server capable of handling large-scale traffic.

How to Handle Explosive Traffic Growth? Learn to build resilient and flexibly scalable architectures through practical design patterns based on EDA (Event-Driven Architecture) using Kafka, Spring, CDC, and Temporal. Explained clearly and simply with real-world experience from Kakao developers, making it understandable even for non-majors. A hands-on focused course covering real-time data flow, event processing, and microservice integration all at once!

This course is a master class that teaches Kotlin's 🌺 Coroutine, covering everything from theoretical foundations to practical application in a standard manner. It systematically covers core principles and structure, the necessity of asynchronous programming, Coroutine builders and scopes, exception handling, channels, Flow, and other key features frequently used in practice, step by step. Each concept is explained with hands-on examples, making it easy for beginners to understand and immediately apply them. This is the best introductory and practical course for developers who want to build strong Coroutine skills for real-world use.

In this course, rather than covering the theory directly, you will learn how to use Redis effectively in your code through hands-on practice.

This covers effective Redis usage, including precautions and applications, illustrated with examples from real-world practice or renowned historical cases.

Let's build a project using Ktor, the most popular project in Kotlin, and master Kotlin! 😆

This course is a master class that systematically covers the fundamental principles and practical applications of MongoDB. Starting with core MongoDB concepts, you will systematically learn essential topics for practical work, such as database design, CRUD operations, indexing, aggregation pipelines, performance optimization, transactions, and security. It explains topics step-by-step so even beginners can understand, and you can deeply learn the working principles of MongoDB through exercises and examples. This is the best introductory and practical course for developers who want to build strong MongoDB skills for practical work.

I am covering the know-how on how I studied and got a job, starting as a non-major.

You can learn how to send emails using AWS and Spring. Through this, you can study how to create an email verification system.

We will tell you everything about how to build a server and perform uninterrupted deployment for stateful services such as Chijijik and AfreecaTV.

We develop a chat service using web socket/stomp and springboot. We also configure a simple screen using vue.js, which is a relatively easy framework. We also configure multi-server scalability design using redis pub/sub.

I've created the 'MySQL Performance Optimization Intro/Practical (SQL Tuning Edition)' course, easy for non-majors to understand and immediately applicable in practice!

This course proceeds in stages, similar to the actual work, by learning and applying the necessary knowledge while configuring the infrastructure.

Understanding Spring Boot + React.js Login (+Social) Service is a course designed to help you deeply understand the authentication flow between frontend and backend, by directly implementing a practical login system that includes JWT-based authentication and social login (Kakao/Google). The frontend is built on React.js, and the backend on Spring Boot, enabling you to learn step by step the practices used in real service environments, such as the Access Token + Refresh Token approach, user state management using HttpOnly Cookie and Redux, Role-based authorization, and social login integration.

You can quickly and easily learn the basics of authentication and authorization through tutorials using Spring Boot, Spring Security, and JWT.

We will learn about cases where companies such as Line, Google, Carrot, and Kakao actually improved MySQL performance. Let's go beyond simple performance optimization guides and understand the internal workings of MySQL and learn how to use it efficiently.

We will inform you about all the security aspects of migration using MySQL and direct operation of DB Server.

Create your own visual novel game using React, Javascript, SpringAI, and Springboot. Learn how to create a web-based visual novel game using SpringAI and React!

Learn the deployment process in the following order: Manually deploy Spring Boot with Chicken Combo value -> Deploy with Docker -> Github Action CI/CD.

Have you ever wondered "how" the many Java libraries and frameworks you use provide this functionality? In this course, learn how to manipulate various codes or objects provided by Java and take your Java skills to the next level.

I'll show you how Java backend developers using IntelliJ can maximize productivity with Claude Code. I'll especially help those using Windows environments completely solve vibe coding environment issues.

Learn Springboot + Flutter RestAPI Board Creation Faster Than Anyone Develop a CRUD server with Springboot and create your own board with Flutter!

I learned it the hard way, so you can learn it the easy way I've discarded unnecessary theory and included only the SQL essentials. Quickly build your SQL confidence.

I've created a beginner-friendly and practical 'Introduction to Elasticsearch' course!

Handling media (video, audio) on the web is now easier than ever! Learn the MediaStream API and WebRTC by following along step by step.

Perfectly master the working process of MCP by creating a TodoList with Claude and IntelliJ.

AI is no longer a choice but a matter of survival. Reduce development time from 3 days to 30 minutes, delegate repetitive tasks to AI, and focus on solving more important problems. With AI-native development methods that you can apply immediately in real work rather than just theory, we'll show you the definitive way to be recognized as "the developer who's good with AI" at your company.

Datalian's SQL basics lecture with over 10,000 cumulative students and rich online/offline lecture experience. Learn SQL basics theory and solve 10 HackerRank problems together.

I have summarized the essential SQL SELECT statements and basic usage of Google Sheets that I learned while working as an analyst at a service company.