Learn Ultra-Low Latency Messaging and Distributed Systems with NATS from a Naver Interviewer

Most developers still remain stuck with Batch and CronJob when talking about data processing. However, in real service environments, data is constantly being generated, and if you can't process that flow immediately, it leads to delays, bottlenecks, and consistency issues. I too have directly experienced real-time recommendation, state synchronization, and event delay problems in high-traffic environments, and have countless times wondered, "Is it right to handle this with batch processing?" This course starts from exactly that question. Using Apache Flink, it explains from a practical perspective how to compute data the moment it flows, safely manage state, and produce accurate results based on Event Time. Rather than simple theoretical explanations, you can experience how real-time stream processing systems are designed and operated through actual source code and architecture. For those who found real-time processing vague, or were curious about the world beyond messaging, this course will provide clear direction.

This course explores microservice architecture and distributed environments not as a simple list of technologies, but from a 'design perspective' required in actual work and interviews. Starting from the differences between monolithic and MSA, it progressively covers incremental migration strategies, modular monoliths, clean architecture and hexagonal architecture, clearly explaining why each choice is necessary and the trade-offs involved. Through hands-on practice, you can directly verify the intent of the structure and learn about core issues inevitably encountered in distributed environments—such as data consistency, transactions, inter-service communication, and failure handling—through realistic scenarios. Based on actual questions and perspectives from Kakao interviewers, this course aims to go beyond simple knowledge acquisition and elevate your way of thinking about distributed systems to the next level.

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.

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.

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 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.

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 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.

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

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 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.

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! 😆

Kotlin mastery via virtual payment server course.

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.

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.

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.

This course explores microservice architecture and distributed environments not as a simple list of technologies, but from a 'design perspective' required in actual work and interviews. Starting from the differences between monolithic and MSA, it progressively covers incremental migration strategies, modular monoliths, clean architecture and hexagonal architecture, clearly explaining why each choice is necessary and the trade-offs involved. Through hands-on practice, you can directly verify the intent of the structure and learn about core issues inevitably encountered in distributed environments—such as data consistency, transactions, inter-service communication, and failure handling—through realistic scenarios. Based on actual questions and perspectives from Kakao interviewers, this course aims to go beyond simple knowledge acquisition and elevate your way of thinking about distributed systems to the next level.

From Docker, Kubernetes to microservices, CI/CD, and service mesh, you can easily learn not only the basic theory but also the actual application implementation through examples. By organizing only the core contents necessary for actual use, it provides a starting point for learning about the element technologies covered in the lecture.

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.

Learn what problems can arise when implementing a first-come, first-served event system and how to solve them.

mongoDB, NoSQL You hear a lot these days, but is it still an unfamiliar database? Aren't you using it like a relational database (RDS/SQL)? No matter how good the technology is, if it's not used correctly, it will have the opposite effect. That's why we often see cases of failure in using MongoDB. This lecture will teach you everything from basic concepts to practical know-how so that you can use MongoDB as MongoDB-like as possible.

Instead of long and boring theories, you can learn them one by one through short practical exercises, and as you flesh them out one by one, you will soon be able to experience the overall architecture composition.

How to Use Storybooks A to Z. We show you everything about storybooks.

From concepts to unique projects, master JavaScript and React all at once with this course. Short learning, long application - a 17-hour All-in-one course!

A portfolio-focused course on directly deploying React frontend and SpringBoot backend to AWS cloud! This course is helpful for those who want to quickly deploy frontend and backend projects to their portfolio! You'll be able to practice step-by-step in a short period the knowledge needed for deployment, from server setup to Docker, Domain connection, Nginx, and HTTPS implementation!

A course that helps you understand core JavaScript concepts and practice explaining them verbally in interviews

You may already be familiar with OAuth 2.0, having used it for simple logins with accounts like Google or GitHub. Social login is an extension of OAuth 2.0, and its core technology is in the OAuth 2.0 authorization framework. If you understand the principles of OAuth 2.0, you can develop the ability to implement and adjust it appropriately to your needs.

Build and deploy community applications using the MERN Stack (MongoDB, Express, React, Node + Firebase)

This is a course where you can learn ES6+ and functional programming. This course covers and applies the iterable/iterator/generator protocols of ES6+ in detail. You can learn functional programming based on iterables, map/filter/reduce, pipelines, lazy evaluation through generators, promise composition, concurrency/parallelism, async/await and asynchronous error handling, etc. Master this course and practice to become an intermediate JavaScript developer!

I've seen a lot of people around me who are just starting out with coding. Those with experience say that JavaScript is easy, but those who are new to it can't help but find it difficult. That's why I've prepared easy and informative content for those who are just starting out with coding. 💪🙂

Let's learn from basic syntax to advanced concepts while developing a SPA with vanilla JavaScript🔥

Through this course, you can learn about Docker and set up a CI environment.

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

This is a lecture on creating a map service from start to finish using the MERN stack (feat. TypeScript). Let's create each part step by step by looking at the official API documentation.

We will cover the concept of machine learning in a JavaScript environment. We will cover the form and code of implementing machine learning with JavaScript and TensorFlow.js.

💡 Even non-developers can go from startup MVP to monetized service in just 10 hours with AI! 💰 Development that used to cost tens of millions in outsourcing fees now completely solved for 120,000 won 🎯 Complete 5 real business projects including business card recognition, sentiment analysis, and location analysis 🔥 If you're a planner, marketer, or aspiring entrepreneur, implement ideas without developers ⚡ Start now and acquire lifelong development independence skills!