Practical preparation for coding tests and interviews, directly taught by interviewers from Naver, Kakao, Line, Coupang, and Baemin.

This course provides a step-by-step learning path, ranging from the fundamental usage of MySQL to advanced techniques required in real-world production environments. It covers a wide range of topics, including data modeling techniques based on various case studies and practical data, evaluating the effectiveness of Foreign Key designs, analyzing Google Calendar schema DDL, and modern DDL design principles. Through this course, you will gain an in-depth understanding of how to utilize MySQL as a core system component rather than just a simple database.

Develop a scalable order processing system with real-time event streaming capabilities using Spring Boot 3.x + Kotlin to build a Kafka cluster, leveraging PostgreSQL CDC, 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.

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

How do you handle exploding traffic? Learn how 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 a Kakao developer, making it accessible even for non-majors. A hands-on, practical course covering real-time data flow, event processing, and microservice integration all at once!

Most developers are still stuck on Batch and CronJobs when it comes to data processing. However, in real-world production environments, data is generated continuously, and failing to process that flow immediately leads to latency, bottlenecks, and consistency issues. Having personally dealt with real-time recommendations, state synchronization, and event delay problems in high-traffic environments, I’ve often asked myself, "Is batch processing really the right approach for this?" This course begins with that very question. It explores how to use Apache Flink to perform computations the moment data flows, manage state securely, and produce accurate results based on Event Time—all from a practical perspective. Beyond simple theoretical explanations, you will experience how real-time stream processing systems are designed and operated through actual source code and architectures. For those who found real-time processing vague or were curious about the world beyond messaging, this course will provide a clear sense of direction.

I'll show you how to use Redis effectively, along with its precautions and best practices, using real-world examples from actual work environments and well-known case histories.

Learn the process of building essential Observability in a Microservices Architecture (MSA) environment from basics to practical application. Master standardized data collection using OpenTelemetry, trace storage and search through Grafana Tempo, and visualization using TraceQL through step-by-step hands-on practice. You can learn how to track service flows through distributed tracing, identify bottlenecks, and analyze the root causes of failures.

Learn SAGA transaction management techniques for maintaining data consistency in distributed environments through hands-on practice. Build 3 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 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.

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 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.

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

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.

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

When you're doing backend development, at some point you face this dilemma. As services grow and traffic increases, there comes a moment when simple REST communication and CRUD structures feel limiting. I experienced the same problem in real-world work and went through many trials and errors between performance and structural complexity. The solution I chose in that process was NATS. Its simple configuration based on a single binary, ultra-low latency performance in microseconds, and the fact that it provides just the right amount of essential features for real work—from Pub/Sub to Queue Groups and JetStream—made it a very practical choice in actual service environments. This course is not about listing NATS features. Based on the problems I faced in real work, I explain with code and flow diagrams which situations led me to choose NATS, why, and how I designed the architecture. This is a course designed to help everyone—from those new to messaging systems, to backend developers preparing for jobs, to senior developers contemplating better architectures—understand distributed systems and grow to the next level.

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.

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.

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.

Coding Test Lecture taught by a World Competition Participant! Now, don't solve by feeling, solve with confidence!

This [Practical Employment] lecture covers only the most practical content. It comprises a lecture + e-book (total 144 pages). 1. This course strategically teaches the entire practical job search process, from interpreting job postings to resumes, cover letters, and interviews. 2. Students will learn to structure and articulate their experiences, and acquire tailored strategies and writing skills for each recruitment stage. 3. Ultimately, you can define your own career direction and complete actionable employment strategies.

This course is for job seekers and career-changing backend developers preparing for coding tests with JAVA. We clearly identify question types by analyzing 195 actual past exam questions.

From documents to interviews, the A-Z of designer employment is included. We will show you in detail how to increase your chances of passing by watching the interview process of an actual applicant that you cannot see anywhere else.

If you are seeing this email today, saying, “After careful consideration, we regrettably decided not to proceed with the next process with ooo,” don’t miss out on Pro-Igicler’s developer know-how!!

I will share all the trials, errors, and know-how I experienced on my journey from being a manufacturing web developer to becoming a back-end developer at a commerce/K company portal service company. Don't you all go through the same trials and errors!

Through this lecture, students will be able to learn the basic and post-processing technology flow of semiconductors, and will be able to learn the content necessary to prepare for interviews at post-processing semiconductor companies.

For those who have chosen a career in information security/information technology and are preparing to move to large corporations/financial institutions, we will reveal our strategy for passing the exam. A current CISO who has personally recruited and recommended numerous people will share his secrets for passing the exam. He has heard from his acquaintances, security company CEOs and executives of large companies, and compiled a recruitment bible by collecting a vast amount of recruitment secret data.

Master Algorithm Problem Solving with 100 Essential Silver Level Problems from Baekjoon Online Judge

Learn Python from scratch by fully utilizing ChatGPT. Rather than tedious conceptual explanations, the focus is on students directly experiencing coding and developing problem-solving skills through example problems and practical exercises. After mastering Python's basic syntax, you can build your skills by solving various problems in Level 1 and Level 2. Furthermore, you can identify and supplement your weaknesses through an Exam structured like a real test. By regularly solving problems and utilizing ChatGPT, students can have a memorable learning experience without feeling bored.

Based on problems from major game companies like Nexon, NC, Krafton, and Netmarble, this explains essential C++ concepts and problem-solving skills that job seekers and career changers must know. Pass technical tests and interviews in one go with 10 years of actual exam questions.

This course explores the essential RPG game feature of "pathfinding" while naturally teaching data structures and algorithms. It quickly covers common technical interview questions, allowing you to prepare for coding interviews in a short period.

This is a [Backend, Resume Enhancement] class prepared for job seekers and junior developers.

Listening to the interview speech can help you pass the interview with flying colors.

When learning Swift, the iOS programming language, it can be confusing when multiple concepts appear all at once. That's why I created this course with the principle that "when understanding a new concept, only previously learned concepts should be used." So this course is meticulously designed with a sequential structure between concepts, where only one new concept appears at each stage, and no other unfamiliar concepts appear at all. One concept per minute, 180 concepts total. From the basics of variables and constants to understanding memory structure from a CS perspective, and even the latest syntax for asynchronous processing. In 3 hours, you'll learn 180 core concepts in the designed order.

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

This is a game development & algorithm course that focuses on the algorithms and principles of 2D game development from the ground up using Windows API and C++.

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

We'll tell you what to do and what not to do when you have to give a technical/business presentation.

This is a practice-focused problem-solving course for JavaScript beginners. It is structured to allow you to naturally learn core concepts and internalize syntax by solving approximately 1,500 step-by-step problems on your own.