Be a Good Boss to AI! - Choosing a Backend Stack

Are you overwhelmed by AI-generated backend code and unsure where to look? Learn how to identify missing conditions in requests, APIs, data, concurrency, authentication, and caching—and what requirements to give the AI and what criteria to use when reviewing its output.

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.

The order is confirmed, but the notification is delayed. The response is faster, but if tasks disappear after a restart, where should you look first? Using real execution records from virtual orders, we’ll walk through RabbitMQ delivery and acknowledgments, deduplication, the Outbox pattern, retries, ordering, and backlogs. We’ll also establish a way to find and complete work that remains unfinished even after a fast response.

Even if the SQL is written correctly, is your data still protected in production? Access and permissions, recovery and safe changes, scaling and replication, MongoDB, Redis, DynamoDB, and search. This is Part 2, where you’ll learn what else needs to be defined to uphold the data standards established in Part 1 in production and across other storage systems.

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!

AI-generated SQL ran without errors—but does that mean the result is correct? Learn to identify missing criteria in a row’s meaning, values, queries, aggregations, changes, and concurrent requests, as well as which data rules to communicate to AI and what evidence to use when reviewing the results.

I have created a course titled 'Introduction to MySQL Performance Optimization & Practice (SQL Tuning Edition)' that is easy for non-majors to understand and can be applied immediately in practice!

An analysis of 27 commonly asked distributed systems interview questions with Channel Talk interviewers! Learn about everything from server scaling to sharding, replication, and consistency through diagrams, and prepare for system design interviews with sample answers and a post service design case study.

Does game backend development feel daunting and vague? With know-how gained from firsthand experience with numerous projects, I will show you how to perfectly integrate complex Firebase features into actual games. We will connect Firebase to a Unity 6 Watermelon Game to implement online features such as login, cloud database (Firestore) save/load, rankings, bulletin boards, and mailboxes. This is a practical course that also covers security rules, Remote Config operations, and code design based on a layered architecture (UI, logic, and data access).

There are moments when a price changes in another window but doesn’t show up on your screen, even though it says “Connected.” Let’s walk through real execution logs, step by step—from how to choose between polling, long polling, SSE, and WebSocket with two virtual auction windows open, to resynchronizing after a disconnect and tracking changes across multiple servers and proxies.

In the software system design course taught by Silicon Valley engineers, you will learn the design principles and architectural patterns of large-scale systems and how to build stable and scalable software solutions. In addition, you will cover performance optimization and fault response strategies through practical cases.

From the fundamentals of MySQL usage to the advanced techniques required in real-world service environments, you will learn progressively. The course also covers a wide range of topics, including data modeling techniques based on various cases and practical data, evaluating the effectiveness of Foreign Key design, analyzing the Google Calendar schema DDL, and modern DDL design principles. It provides an in-depth understanding of how to use MySQL as a core component of a system, rather than merely as a database.

This course trains you to think in terms of frontend system design through real-world service cases such as Threads feeds, Amazon shopping carts, the Netflix streaming UI, Google Docs collaborative editing, Micro Frontends, Agentic UI, and Observability.

In an era when AI can write code, developers need to be better than ever at deciding what to design, why, and how. Yet many developers rely on hands-on experience or learning individual technologies rather than studying architecture systematically. Even when they know architecture patterns, they may find it difficult to decide when and why to apply them, or to explain and evaluate the rationale behind design decisions. This course is a comprehensive software architecture program designed to address these challenges. It draws on the iSAQB curriculum, research and evaluation methods from CMU SEI, ISO/IEC quality models, and specialist books on software architecture, while incorporating 25 years of development and design experience gained at game companies, systems integration firms, and startups. The course comprises 8 sections and 59 lessons, covering everything from fundamental architecture concepts, quality-focused thinking, and design principles to architecture styles and patterns, documentation and evaluation, practical design case studies, operations, and the growth and leadership of architects. Rather than teaching how to use specific technologies or frameworks, the course focuses on design principles and decision-making criteria that remain useful even as technologies change. It’s a journey to grow from a developer who knows about architecture into one who thinks and makes decisions like an architect.

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.

This lecture comprehensively organizes the content that would be good for those who want to get a job as a new Spring Java backend developer, especially those who are about to have an interview.

In this course, you will be able to create a Reddit website from scratch, step by step.

Regardless of the field! This is a lecture that covers the core fundamentals that developers must know in practice in an easy + code-oriented way. I highly recommend this lecture to all junior developers and job seekers who want to grow.

I have created a course titled 'Introduction to Redis/Practical Application (Query Performance Optimization Edition)' that is easy for non-majors to understand and can be applied immediately in practice!

It has become easier to write code with AI, but it is still important to understand how the services we build are structured and operate. We need to know the overall flow—how the frontend and server connect, where data is stored, and what to consider as the number of users grows—so we can ask the right questions. I also studied by building up my knowledge one step at a time, starting with the basics. In this course, I first lay out the big picture, then suggest a way to learn by connecting the details to it. “The Age of AI One-Click Coding, a New Direction for Development: The Big Picture of System Design” is the introductory course in the System Design series. Across 74 lessons, we explore a broad range of topics, from the basic structure of services to data, communication, security, deployment, and operations. Familiar examples involving orders and reservations, along with diagrams that build up step by step, help explain why each concept matters. You don’t need to memorize every term or understand how to implement everything from the start. The goal of this course is to help you follow along comfortably, like watching an educational program, and build a big-picture understanding: “So, these are the kinds of problems that come up, and these are some ways to solve them.” Along with the videos, you’ll get an HTML textbook containing detailed explanations, diagrams, and sample code. You can follow the overall flow in the videos and revisit anything you’re curious about in the textbook. Practical implementation and in-depth coverage of specific topics will continue in the follow-up series.