Core Banking Server Features Implementation with Multi-Module Architecture [ Kotlin & Spring ]

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.

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.

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!

Learn SAGA transaction management techniques for maintaining data consistency in distributed environments through hands-on practice. Configure three microservices using Spring Boot and Docker, and implement both Orchestration and Choreography patterns with Kafka and MySQL. Through this course, you can master core concepts that are immediately applicable in real-world scenarios, including distributed transaction operation principles, compensating transaction design, and failure recovery handling.

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.

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 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.

Kotlin mastery via virtual payment server course.

This course covers RPC communication techniques that maximize performance in large-scale MSA (Microservice Architecture) environments. Going beyond simple gRPC practice, you'll learn how to implement stable and efficient inter-service communication in real production environments where hundreds of microservices operate simultaneously. Based on Golang, the course covers Protocol Buffers (proto) syntax writing, automatic code generation and service implementation, gRPC structure and advantages over existing RPC, and performance optimization strategies with a practical focus. To ensure easy understanding for non-majors and server development beginners, the course provides step-by-step explanations from RPC concepts to gRPC's internal operating principles, enabling you to develop practical skills that can be immediately applied to real services.

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.

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.

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.

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

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

You can learn about JWT and ws communication using Spring Boot, and how to handle high TPS.

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 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.

Learn practical strategies for designing efficient and scalable database structures that accurately reflect the complex requirements of real-world scenarios.

"I have a backend technical interview in a week, what should I start with?" The secret to answers that make interviewers nod in approval Master the actual answer patterns of Naver, Kakao, Coupang, and Toss successful candidates in just 3 days!

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

Through this lecture, you can learn about the characteristics and background of the Kotlin language, grammar and operation principles, usage examples, and things to be careful of when using Java and Kotlin together.

This is a course for job seekers / career changers preparing for coding tests in JAVA as backend developers. We analyze 195 actual exam questions to clearly explain the question types.

A Java advanced project course for beginner developers who want to develop practical skills! We'll build a console-based kiosk ordering system together using Spring Core, JdbcClient, and H2 DB.

# Building an 'Intelligent Collaboration' Expert Agent Team Using Spring AI Router Pattern + RAG + MCP Beyond Single Agents to Architecture: The Definitive Guide to Router Pattern and Agent Isolation Design

Java is not difficult to learn. It's just that it becomes difficult because you learn too many unnecessary things. There are things in technology that can only be understood when you reach that stage. But, it's just hard because you try to cram too much unnecessary stuff into your head. Technology is experience. Let's learn quickly and simply!!

Learn Java-based data structures and algorithms, and grow into a competitive coding expert with practical problems!

In this lecture, you will learn the basic terms and principles of query tuning for MySQL/MariaDB, and then improve your tuning skills by analyzing dozens of malicious queries.

Spring AI + JPA + MySQL Premium Reservation Agent Backend Development with 'Autonomous Behavior' Beyond Chatbots to Agents: The Definitive Guide to Tool Calling and Prompt Engineering

We enable you to fundamentally understand and resolve issues where Hangeul appears broken on web pages or in databases, or files contain unknown characters.

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.

This is a lecture using the only domestic e-government framework and Layered Architecture, which are widely used in practice but not available in Korea. In this lecture, we will learn how to build the backend and server side of web development using the Spring Framework and the e-government standard framework.

If you can master DB and programming, you should be more than halfway prepared for the information processing engineer exam. Let's take a look at the DB and programming parts, which are worth 45 to 55 points in the practical exam, and pass the written exam steadily.

OODP's 25 patterns teach various methods for object-oriented software design.

What kinds of problems appear in coding tests these days? Solve “practical” problems yourself, reflecting the latest corporate coding test trends. We provide proven problems and solutions to effectively build your algorithm and problem-solving skills. (with Java)

The TDD & Clean Code masterpiece lecture, recommended by many senior developers in Korea to junior developers for over a decade.

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