Practical System Design for Juniors in the AI Era: We’ll Fill in the Experience Gap for You

You’ve written SQL with JdbcTemplate before, right? I’m sure everyone has experienced the frustration of having to modify both the SQL and the RowMapper every time a single column changes. This course begins with that pain. A single SELECT using plain JDBC takes 35 lines. You open a Connection, create a PreparedStatement, iterate through the ResultSet, and if you forget even one close(), the server goes down. After typing through this hell yourself, encountering JPA’s one-line save() makes you feel, not just understand, “This is why people use JPA.”

How does the architecture change when an LLM is integrated into an existing backend? Going beyond simple LLM API calls, this introductory system design course helps you understand the core components of AI services—such as Model Routers, LLM Gateways, and Vector DBs—and progressively design operational AI service architectures, including RAG and AI Agents. It helps those who want to build their own LLM-based AI services quickly learn the design process.

This course takes you from the fundamentals to advanced, real-world container workflows using Docker and Kubernetes. You will start by learning containers from the ground up, understanding how Docker works and why it is widely used in modern DevOps environments. You’ll run Docker, Docker Compose, and Kubernetes locally to improve software development, testing, and deployment workflows.

Beyond the basics of API design, CRUD implementation, and JWT authentication, all the way to backend architecture design! This is an introductory system design course to help you create 'your own backend architecture' so you can confidently discuss design experience in interviews.

Messy code, a flood of requirements... If you're looking for a breakthrough with AI, Learn how to become a "high-performing developer" by leveraging AI in legacy environments, taught by the former VP of Engineering at Toss Payments. Legacy code isn't going anywhere, even in the age of AI. It’s no exaggeration to say that every company has legacy code, unless they were founded today. So, how should we utilize AI in this reality? In this course, the former VP of Engineering at Toss Payments, who led a large-scale payment service organization, demonstrates firsthand how to work effectively using AI in legacy environments. This isn't just a course about how to use AI or basic coding skills. The goal is to help you develop your "critical thinking" as a developer and truly understand what it means to work effectively.

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.

The most definitive practical guide for developers who want to integrate AI into their Spring projects right away! Beyond simple LLM API calls, you will perfectly master building production-level AI environments that can be immediately applied to real business logic using RAG and MCP.

DevOps Interview Preparation: Master your interview preparation for Git, Docker, CI/CD, Terraform, Ansible, Kubernetes, and Monitoring.

DevOps Interview Preparation: Master your interview preparation for Cloud, CI/CD, Infrastructure as Code, Monitoring, Linux, Docker, and Kubernetes.

This is a text-based course that conducts mock interviews based on your résumé.

This is a DevOps course based on practical experience in Silicon Valley. It goes beyond theory to cover content that can be applied immediately in the field. You will learn how to develop using Generative AI (Vibe Coding), set up CI/CD tools in a Kubernetes environment, and implement strategies to keep operating costs at $0. We will cover configuring a production environment without additional costs by running DB, Redis, S3, and batch jobs inside Kubernetes, and you will master building automated pipelines using GitHub Webhooks and Jenkins through hands-on projects.

IntelliJ IDEA Conf 2025 is an annual online conference hosted by JetBrains that provides valuable sessions for Java and Kotlin developers. It covers various topics including AI adoption, Spring Boot, Gradle, Kafka, database management, and also shares insights on cloud integration, secure coding, developer performance improvement, and advanced development techniques. This conference is open to both professional and beginner developers, offering opportunities to explore the latest technologies along with productivity tips for writing high-quality code faster.

It explains almost everything surrounding the cloud in an easy-to-understand manner. If you listen to it before the actual practice, you will be able to understand development or infrastructure cloud well.

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

Uncover true value in the age of data! 📊 Designing applications focused on data has now become essential. Develop the insight and skills your company wants with the latest trends and practical case studies. Start now with efficient data processing and design secrets! Your next step, leap into the data-driven world!

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.

Building your own emotional diary service with Spring AI + React It's time for our 4th project with Neo + Essential!

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

Building an 'Intelligent Collaboration' Expert Agent Team Using Spring AI Router Pattern + RAG + MCP Beyond a Single Agent to Architecture: The Standard for Router Patterns and Agent Isolation Design

I highly recommend Spring AI to developers using Spring Boot and React, as well as those considering the introduction of AI systems in corporate environments. This course goes beyond a simple introduction to libraries; it helps you understand the core concepts and internal structure of Spring AI, and strengthens your practical implementation skills through various hands-on examples. The course is based on Spring AI version 1.1.x and provides continuous technical support and expansion strategies to ensure you can adapt to future version upgrades. Furthermore, we expand the practical value of Spring AI technology by utilizing MCP (Model Context Protocol) to achieve cross-domain context integration, AI linkage in distributed environments, and AI architecture design suitable for enterprise environments. With the goal of building AI systems that can actually be deployed in corporate settings, this will serve as a practical guide that balances theory and hands-on experience.