Kakao Interviewer's Hands-on Spring Batch: Everything About Large-Scale Data Processing

Systematically learn the distributed NoSQL database Cassandra, from basic concepts to practical application. Develop high-volume data processing capabilities through practice-oriented theory and hands-on exercises, including data modeling, query optimization, and cluster configuration. Even without prior database experience, you can grow into a Cassandra expert based on the know-how of a current Silicon Valley developer.

This course goes beyond simple CRUD-level database usage to help you acquire PostgreSQL skills necessary for the AI era from a practical perspective. Based on AI development experience in Silicon Valley, you will learn step-by-step how to design and utilize JSON, indexes, transactions, and even pgvector in real-world services, while mastering methods to solve complex data structures and performance issues.

When you find yourself constantly modifying Swagger documents, aligning API specs, and communicating back and forth with the frontend, you start to wonder, "Why am I doing the same thing twice?" I felt that same frustration in the field, which led me to dive deep into GraphQL and develop an interest in data-driven design. This course isn't just about simple GraphQL syntax; it covers why it emerged to solve real-world service problems, along with practical considerations like Resolver structures, the N+1 problem, and Federation. I have designed this course to help you naturally learn how to reduce communication costs between developers and design a more flexible API structure.

You may have felt frustrated using Redis without being able to explain why it should be designed that way or why certain patterns emerged. Through my experience in both practical development and as an interviewer, I have treated Redis not just as a simple cache, but as a core component that determines service stability and scalability. This course is not about memorizing commands; instead, I will share my experiences on which structures to choose in real traffic environments and their trade-offs, helping you establish the criteria to explain these concepts confidently in both interviews and practical work.

It was created to solve the "overwhelming problem of not knowing where or how to start with Kubernetes." Based on hands-on experience operating financial infrastructure, it is designed to help you understand the actual build and operation flow rather than just simple theory. Through a learning process that covers the relationship with Docker, YAML, Pods, Deployments, and Services, learners will master Kubernetes not just as a "concept," but as a "usable skill."

How will you handle exploding traffic? Learn how to build resilient and flexibly scalable architectures through practical EDA (Event-Driven Architecture) design patterns using Kafka, Spring, CDC, and Temporal. A Kakao developer shares real-world experience with clear, easy-to-follow explanations that even non-majors can understand. A practice-oriented course covering everything from real-time data flow and event processing to microservice integration!

Build a scalable real-time event streaming order processing system using Spring Boot 3.x + Kotlin, establishing a Kafka cluster, and leveraging PostgreSQL CDC, Debezium Connect, and Apache Avro schemas.

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.

This course is for developers who want to find fundamental solutions in environments where response times slow down as traffic increases, thread pools are quickly exhausted, and bottlenecks worsen with more external API calls. It helps you look at problems from the perspective of changing the architecture itself, rather than simply scaling out servers. Through this course, you will first understand the limitations of the traditional Spring MVC "Thread per Request" model. You will examine at the code level why throughput doesn't increase even when CPU resources are available, and exactly how blocking I/O occupies system resources. Next, you will learn the concepts and standard specifications of Reactive Streams and master how to handle data streams using Reactor's Mono and Flux. Beyond simple usage, you will learn through hands-on practice how data flows start, how they are consumed, and how throughput is controlled. In particular, you will directly implement design patterns that prevent OOM (Out of Memory) or overloads using Back Pressure. Additionally, you will understand the event loop-based processing structure of Spring WebFlux and conduct comparative exercises on how Non-Blocking I/O operates during actual request processing. By placing MVC and WebFlux side-by-side to verify their structural differences, you will also establish criteria for when to choose Reactive. This goes beyond simply "learning asynchrony." You will learn how to handle more requests with fewer threads, how to maintain a stable flow in environments with high external API dependencies, and develop the design intuition to secure throughput in high-concurrency environments.

This course focuses on solving the problem of getting stuck in interviews and practical work due to a lack of understanding of why certain structures and configurations are necessary, rather than just teaching how to configure NGINX. Based on experience evaluating numerous candidates as an interviewer for companies like Naver, Kakao, and Toss, I explain how to describe and utilize NGINX from the perspectives of performance, scalability, and operations through hands-on practice. The core of this course is to help you develop a mindset capable of tracing traffic flow and troubleshooting problems, rather than just memorizing configuration values.

Learn how to design and handle large-scale data architectures that process hundreds of billions of records using only pure SQL and core MySQL features, alongside 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.

Learn the SAGA transaction management technique for maintaining data consistency in distributed environments through a hands-on approach. You will configure three microservices using Spring Boot and Docker, and implement both Orchestration and Choreography patterns using Kafka and MySQL. Through this course, you will master core concepts applicable to real-world scenarios, including the operational principles of distributed transactions, designing compensating transactions, and handling fault recovery.

This course goes beyond simply teaching you how to use Docker as a tool; it approaches the subject from the perspective of solving the real-world dilemmas and problems encountered in professional practice. From unpredictable errors caused by differences between development and production environments, to configuration mistakes stemming from vague concepts of images and containers, and even the anxiety of "how much do I need to know to survive in the field"—this course explains it all based on firsthand experience operating financial infrastructure. Rather than just listing commands, it focuses on real-world cases: why certain structures are necessary, how to design images for easy maintenance, and how to handle containers for stable service operation. In particular, by prioritizing hands-on practice over theory, the course is designed to elevate students from simply "knowing how to use" Docker to "understanding it from an operational perspective" through visual comprehension and direct experience. This course provides practical standards and direction for those new to Docker, those who have used it but lack a clear conceptual grasp, and developers looking to take their infrastructure intuition to the next level.

Develop a scalable real-time WebSocket chat server capable of handling high traffic by building a 3-instance cluster with Spring Boot 3.x and Kotlin, utilizing Redis Pub/Sub for distributed messaging and Nginx as a load balancer.

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.

This course was created to solve a common problem many people face while preparing for developer jobs: "I studied CS and data structures, but I get tongue-tied during interviews." While conducting actual interviews at companies like Naver, Kakao, and Toss, I noticed that most candidates have memorized concepts but cannot explain why those concepts are necessary or how they are applied in real-world situations. Rather than simple rote memorization, this course teaches you how to understand the interviewer's intent and provide more persuasive answers to the same questions. Whether it's the OSI 7 layers, data structures, or coding tests, we focus on why you need to know them, when they are used, and how to speak about them to receive a positive evaluation in an interview. This course is for those who want to become developers who can explain what they understand in their own words, rather than just giving the same answers as everyone else.

At some point in backend development, you start to have these concerns. It's that moment when services expand and traffic increases, and you begin to feel the limitations of simple REST communication and CRUD structures. I experienced these same issues in the field and went through much trial and error balancing performance and structural complexity. The solution I chose during that process was NATS. Its simple configuration based on a single binary, ultra-low latency performance in microseconds, and the fact that it provides essential features—from Pub/Sub to Queue Groups and JetStream—without being overkill made it a very practical choice for real-world service environments. This course is not just a list of NATS features. Based on the problems I faced in practice, I explain through code and workflows why I chose NATS in certain situations and how I designed the architecture. This course is designed to help everyone—from those new to messaging systems to backend developers preparing for employment and senior developers considering 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.

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

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.

How will you handle exploding traffic? Learn how to build resilient and flexibly scalable architectures through practical EDA (Event-Driven Architecture) design patterns using Kafka, Spring, CDC, and Temporal. A Kakao developer shares real-world experience with clear, easy-to-follow explanations that even non-majors can understand. A practice-oriented course covering everything from real-time data flow and event processing to microservice integration!

We will refactor a web application built with Java + Spring Boot to Kotlin + Spring Boot and implement additional requirements. In the process, we will use Junit5, SQL, JPA, and Querydsl, and cover the pros and cons of various methods from the design and implementation perspectives.

Learn the SAGA transaction management technique for maintaining data consistency in distributed environments through a hands-on approach. You will configure three microservices using Spring Boot and Docker, and implement both Orchestration and Choreography patterns using Kafka and MySQL. Through this course, you will master core concepts applicable to real-world scenarios, including the operational principles of distributed transactions, designing compensating transactions, and handling fault recovery.

This is a lecture for people who are starting development for the first time. It's about programming thinking, which should come before development languages or UI frameworks.

It covers just two things properly: object-oriented programming and the JVM! Plus, it throws in linked-list-based linear data structures.

Refactoring is one of the basic skills that a software engineer should have. This course is designed to explain and practice various code smells and refactoring techniques in a more practical way using IntelliJ and Java.

Starting with java.io, you can learn how to develop high-performance input/output systems based on NIO and NIO.2. Most importantly, the moment you master file I/O, we'll enable you to master high-performance server development as a bonus!

Experience the power of Type Safe SQL with jOOQ!

It's time to master Java's various features so you can apply them in practice! ^^ Let's make it completely yours by solving algorithm problems together. Teacher Eun-jong will continue to be with you in Part 2.

This course is designed to prepare you for the Information Processing Engineer practical exam solely through solving previous exam questions. Instead of unnecessary theories or vast amounts of content, it focuses on past exam questions that are repeatedly featured, allowing you to connect your learning directly to passing the exam. You can quickly grasp core points and question patterns by reflecting on the latest trends, and even learn tips for writing answers through the problem-solving process. This lecture is optimized for examinees aiming to pass efficiently in a short period of time.

Pass the Information Processing Engineer practical exam in one go! We provide only the essentials, focusing on code and theory. Master past exam questions perfectly! Open the door to passing with our systematic lectures. 🏆 2024 Inflearn Rookie Award 🏆 2025 Students' Pick Award Winner

Knowing design patterns will make it easier to learn not only Spring but also many other technologies and programming languages. It will also help you develop more flexible and reusable object-oriented software.

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.

An AI system that grades and reviews your code in just 5 seconds—imagination becomes reality. This course is an all-in-one project curriculum for creating a **'GitHub PR Auto-Analysis and Grading Bot'** using Spring AI. When a student submits an assignment (Pull Request), the server detects it, and the AI analyzes the code changes (Diff). The grading results are then stored in a database, feedback is automatically posted as a GitHub comment, and the student can check their results on a dedicated dashboard. From backend to AI integration and frontend (Vaadin), all with just Java! This is the ultimate introductory guide for any developer who wants to build their own AI service from A to Z.

In [Java Practical Project: UI Edition], we will create a movie information application that operates solely on pure Java technology using JavaFX. This course is designed to help you deeply understand the "structure connecting screens and logic" by directly implementing UI event handling, asynchronous logic, and user interaction flows in Java before moving on to web and smartphone apps. You will train your structural thinking by separating business logic and UI through integration with Spring Core, and learn how to solve UI performance degradation issues that may occur when fetching movie information from external APIs using asynchronous processing. Through this, you will clearly understand the principles of data flow, event listeners, and thread-based asynchronous processing, elevating your understanding of the Java language itself to the next level. In short, this course is a "practical stage to experience the essence of UI and the core of asynchronous processing with Java before moving to the web." Do not forget that this is not a class for just typing along with code, but a learning experience where you can personally master the principles of connecting UI and logic.

Currently, Android can be developed using the Java and Kotlin languages. You can develop the same Android applications regardless of which language you use. This course covers most aspects of Android application development, from basics to advanced levels, and all code is written using the Kotlin language starting from the fundamentals. Furthermore, it utilizes Google's latest UI library, Material 3. This course primarily focuses on menus, Android application components, threads, and fragments within the overall Android curriculum, and more in-depth topics will be covered in the next course. Soft Campus will always strive to provide the latest lectures. Thank you.

Developing an 'Autonomous' Premium Reservation Agent Backend Using Spring AI + JPA + MySQL Beyond Chatbots to Agents: The Standard of Tool Calling and Prompt Engineering

Create your own visual novel game using React, Javascript, SpringAI, and Springboot. Learn how to make a web-based visual novel game with SpringAI and React! Neo + Essential

Channel Talk interviewers will directly analyze the difference between failing and passing answers to the same question and help you prepare for actual follow-up questions.

This course includes both server (Java+Springboot) and front-end (React, ReactNative, Flutter, Android, iOS) development. Experience building a full-stack bulletin board with this course.