Hello, this is Gym Coding.

Claude Code Master: From AI Development Workflow Basics to Practice has surpassed 8,305 students and 1,021 reviews (4.9 rating) within just 6 months of its launch. Thank you to everyone who joined us, and we have prepared a commemorative discount 🥳

✅ Discount Information

• Target: Claude Code Perfect Mastery

• Discount Rate: 25% Off

• Price: 198,000 KRW → 148,500 KRW

• Period: Monday, June 15, 2026 – Tuesday, June 30, 2026

👉 Enroll now at the discounted price

📣 And one more thing, we are preparing a practical version

We are currently planning Claude Code Masterclass: Professional Edition. Beyond the basics, we plan to cover content that is useful when using Claude Code in actual work.

While using Claude Code

• where you got stuck

• what was the most difficult part

• What specific areas you would like to learn more about in depth

Please leave your thoughts in the comments of this post. I will incorporate the feedback you provide directly into the curriculum for the practical version. The specific points you found difficult will become a chapter in the next lecture.

And we plan to provide a separate discount coupon to current students of the Claude Code Master course when the practical version is released. If you take it now, you'll be able to continue with the next course at a more reasonable price. 😊

😊 To those currently taking the course

If the course was helpful, a single-line review would be a huge help. Leaving even a short, honest review will serve as a great guide for future students and provide me with the motivation to create even better courses. If you haven't left a review yet, please take this opportunity to write a quick line! 🙏
👉 Write a Review

🎯 For those who haven't taken the course yet

We are now in an era where the difference in skill is determined not by whether you use AI coding tools, but by how well you use them. Within just six months of its release, more than 8,300+ people have enrolled, and a wide range of individuals—including not only developers but also marketers, planners, researchers, data analysts, and students—are learning Claude Code together.

Recent Course Reviews
After taking this course, I truly feel this is the most delicate and detailed course I have ever taken. While watching the lectures, you make sure to point out parts that could easily be overlooked, and you naturally comment on what was learned before to provide a review. It sticks in my head much better because the review happens naturally within the flow of the lecture, rather than being a forced review session. Other courses are so busy moving forward that they just skip over things even if you forget what you learned earlier, but this course isn't like that at all.

👉 View course reviews

The practical version is the next step for those who have established a certain level of foundation. So, if you haven't taken the "Complete Mastery" course yet, I recommend taking the foundation course now at a 25% discount before the practical version is released. Only with a solid foundation will you be able to follow the practical version much more easily.

👉 View all Gym Coding courses

Thank you ☺️

Hello, I'm GymCoding!

"I keep getting errors while trying to install Claude Code."
"It's my first time using a terminal, so I feel lost just looking at the black screen."
"I managed to install it, but now I don't know what to do first."

Since launching the course over five months ago, the most frequent questions I've received have been regarding installation and first-time use. That's why I've newly organized and added a complete workflow for Claude Code beginners based on the latest version!

This lecture is not just a video where you simply follow installation commands. It is designed so that even those new to the terminal can install Claude Code without fear and experience completing their first app all at once.

What is covered in this lecture

• Payment Plan Selection Guide — Pro Plan vs. Max Plan, which one should you choose?

• Terminal & CLI Concepts — Explanations that even beginners can understand at once by comparing them with GUI

• Native Installation by OS — macOS / Windows (PowerShell) + Git Bash

• Installation Troubleshooting — Environment variable settings, the most common hurdle (for both Windows and Mac)

• VS Code Integration + Model Change (Sonnet) — Settings for convenient use while saving tokens

• First Practice: Creating a Today's Fortune Web App — Experience a proven AI development workflow: Explore → Plan → Implement

The core of this lecture is for even those new to Claude Code to follow along comfortably and experience the moment their first app is completed!

👉Go to Lecture

😊 To those currently taking the course

This additional session is available to existing students at no extra cost. It will be helpful for both those who were stuck at the installation stage and those who want to organize everything from the beginning once more.

And if the lecture was helpful, even a single line of review is a huge source of strength. If you haven't left a review yet, I would be grateful if you could leave a short one! 🙏

👉Write a course review

🎯 For those who haven't taken the course yet

Now, it is no longer a matter of whether you use AI coding tools or not, but an era where how well you use them defines the difference in skill.

Within just 5 months of its release, over 6,800+ people have enrolled, and a wide range of individuals—not only developers but also non-developers such as marketers, planners, researchers, data analysts, and students—are learning Claude Code together.

Hello, I am a marketer, not a developer.
I felt the limitations of using only GPT, so I started looking for Claude Code lectures. At first, I hesitated, thinking this might be for developers only, but this was the first lecture that made me feel it truly works even for non-developers...
👉 Original Review

Learn how to properly study Claude Code based on official documentation and integrate it into a proven AI development workflow all at once.

👉Enroll now at a special discount price

Thank you! 🙇‍♂

Hello, I'm GymCoding!

• "I'm so overwhelmed by the cost of Claude Code tokens"

• I've been getting so many questions like, "I don't know where my tokens are leaking."

So, I’ve put together an additional lecture to properly address this!

This lecture is not just about simple token-saving tips. It is a practical guide that selects only 4 plugins directly related to token saving from the 171 plugins in the Anthropic official marketplace, covering everything from measurement to automatic blocking in one go.

What we will cover in this lesson

• Where tokens are leaking shown on one screen: How to use session-report — How to analyze token usage by project and prompt, and identify the most expensive prompts using an HTML dashboard

• How to reduce the token tax on every turn using two tools from CLAUDE.md management (revise + improver) to keep your claude-md-management clean, which automatically attaches to every request

• serena MCP, which searches for code by meaning rather than just characters — from the reason it was picked as the #1 tool for saving tokens to installing uv package manager dependencies

• hookify, which prevents Claude's mistakes in advance — among the four, this is the only official tool that goes beyond simple token saving to assist with the core of harness engineering

• The entire workflow to install and activate all four with a single-line command from the Anthropic official marketplace

The core of this lecture is a bundle of practical tools that will help you save tokens using official tools curated directly by Anthropic, and even reach harness engineering with the final one!

👉 Go to the lecture!

😊 To those currently enrolled

Those who are taking the Claude Code Perfect Master course can take the new lecture immediately at no additional cost. It has been added to the end of Section 30 of the existing curriculum, so please check it out!

And if the lecture was helpful, a single line of review would be a huge help. If you haven't left a review yet, I would appreciate it if you could leave even a short one! 🙏

👉 Write a course review

🎯 For those who haven't taken the course yet

Now, it is no longer a question of whether you use Claude Code, but an era where how efficiently you use tokens makes the difference in cost and results.

Within 6 months of release, over 6,600 people are taking the course, and a wide range of individuals, including not only developers but also marketers, data analysts, students, and non-developers, are participating.

Recent Reviews

This is the most meaningful lecture of my life. This is the first time I've seen an IT lecture that is so sincere and updated in real-time, and it will probably be the last. It truly is the best lecture, and I want to recommend it to everyone.

You can now enroll at a special discount price at gymcoding.co/vip. Please be sure to check it out before the discount ends!

👉 Enroll now at a special discount price (gymcoding.co/vip)

Thank you! 🙇‍♂

Hello, this is Gym Coding!

Lately, I've been posting card news on Instagram, Threads, and YouTube communities. I've received so many comments like "How do you make these?" and "You're really good at making card news."

So, I have properly organized it as an additional lecture this time!

This lecture is not just about simple card news production tips. You will create a system where you create card news directly with just a Claude subscription—without separate design tools or AI image generators—and package the entire process into a reusable Skill that can be called up anytime with a single line of command.

👉Go to the lecture!

😊 To those currently enrolled

Those who are currently taking the Claude Code Masterclass can take the new lecture at no additional cost. It has been added to the end of Section 30 of the existing curriculum, so please check it out!

And if the lecture was helpful, a single line of review would be a huge source of strength. If you haven't left a review yet, I would be grateful if you could leave even a short one! 🙏

👉Write a course review

Thank you! 🙇‍♂

Hello, this is Gym Coding!

Lately, I've been posting card news on Instagram, Threads, and YouTube communities. Many people have been commenting, asking, "How do you make these?" or saying, "You're really good at making card news."

So I am preparing a proper video about it! To give you the conclusion first, these card news are all being created using Claude code.Without any separate design tools or AI image generators, it's possible with just a Claude subscription for 0 won in additional fees.

The core of this lecture is "direct control instead of outsourcing" — it's not about leaving it to AI and getting different results every time, but about controlling it with rules to systematically produce consistent results!

I plan to upload it as an additional lecture tomorrow (April 21st). For those taking this course, I will provide the actual card news HTML source I use along with card news creation skills, so you can apply them directly to your own brand's card news instead of just watching the video!

👉View card news examples on Gym Coding Instagram

😊 To those currently enrolled

Those who are currently taking the Claude Code Complete Master course can watch the new lecture immediately at no additional cost. It will be added to the existing curriculum tomorrow, so please check it out.

And if the lecture was helpful, a single line of review would be a huge help. If you haven't left a review yet, I would be grateful if you could leave even a short one! 🙏

👉Write a course review

🎯 For those who haven't taken the course yet

Now is an era where the difference in skill is determined not by whether you use AI coding tools, but by how well you use them.

Since its launch, more than 4,700 people have taken the course, and a wide range of people, including not only developers but also marketers, data analysts, students, and non-developers, are joining us.

I am a complete beginner who knows nothing about development. At first, I started developing with ChatGPT without watching any lectures or having any information. Then, I moved on to Cursor and realized the Claude model is excellent, so I am currently about to start developing with Claude.
I happened to learn about Gym Coding's lectures through someone nearby, and after listening to them, I thought, "I've really been doing this without any plan at all." I feel that after completing this course, I will be able to develop in a more systematic way with a higher level of understanding. Also, the continuous lecture updates!!! I think they will be a huge help. Thank you!^^
— Original Link

You can now enroll at a special discount price at gymcoding.co/vip. Please make sure to check it out before the discount ends!

👉Enroll now at a special discount (gymcoding.co/vip)

Thank you! 🙇‍♂

Hello, I'm GymCoding!

I'm sure everyone has experienced a time when the same AI model works well once but performs poorly another time. Those moments when you wonder why the results are so different even though you used a similar prompt, whether the model is the problem, or if you're missing something.

I feel like many people have been having these concerns lately. So, I've properly organized everything in this additional lecture!

This lecture is not just about prompt tips. I will systematically explain, along with the latest research cases, how the results change completely depending on how you design the environment in which the AI works, even when using the same AI model.

What is covered in this lecture

• Exactly what harness engineering is and why it is gaining attention now

• Anthropic's actual experimental cases — a ruined app for $9 vs. a completed app for$200 with the same model, and what the difference was.

• 3 causes of AI agent errors (Memory loss between sessions, Context Anxiety, Self-Evaluation)

• CLAUDE.md, Permissions, Hooks, MCP, to Subagents — 6 components for designing a harness in Claude Code

• How to re-evaluate harness rules as models evolve

The core of this lecture is not to blame the AI, but to create an environment where the AI can work effectively!

👉Go to the lecture!

😊 To those currently enrolled

Those who are taking the Claude Code Perfect Master course can watch the new lecture immediately at no additional cost. It has been added to the end of the existing curriculum, so please check it out.

And if the lecture was helpful, a single line of review would be a huge help. If you haven't left a review yet, I would appreciate it if you could leave even a short one! 🙏

👉Write a course review

🎯 For those who haven't taken the course yet

Now, we are in an era where the difference in skill is determined not by whether you use AI coding tools, but by how well you use them.

Since its release, over 5,500 people have taken the course, and a wide range of individuals, including not only developers but also marketers, data analysts, students, and non-developers, are participating.

"I am a complete beginner who knows nothing about development.At first, I started developing with ChatGPT without watching any lectures or having any information. Then I moved to Cursor and felt that the Claude model was great, so I am currently at the stage of starting development with Claude. I happened to find out about Gym Coding's lectures through someone nearby, and after listening to them, I thought, 'I have really been doing this without any plan at all.' I feel that after completing this course, I will be able to develop in a more systematic way with a higher level of understanding. Also, the continuous lecture updates!!! I think they will be a huge help. Thank you!^^ " — LExxxx

You can now enroll at a special discount price at gymcoding.co/vip. Please make sure to check it out before the discount ends!

👉Enroll now at a special discount price

Thank you! 🙇‍♂

Hello, I'm GymCoding!

I added a short video.

Why this lecture shows various planning methods,

And it is a lecture that points out the direction of why it is important to deeply understand the specifications rather than a specific tool.

Recently, some people have been requesting additional lectures on various tools such as OpenClaw, Oh My Claude Code, and Superpowers, so I have added this lecture.

👉Go to the lecture!

And the next lecture I am preparing is

This is the Harness Engineering lecture that was requested in the Q&A section. I believe it would be very beneficial for you to understand these concepts!

I would appreciate it if you look forward to it.

Hello, I'm GymCoding!

Harness Engineering is becoming a hot topic, and many people are curious about what exactly it is!

I am currently planning this as an additional lecture.

Harness Engineering is not a new technology. It is a method for systematically designing things you are already using, such as CLAUDE.md, Hooks, and Permissions.

The core point is "change the environment before you change the model." Even with the same Claude, the results vary completely depending on the environment design.

I will be uploading it as an additional lecture soon.

😊 To those currently taking the course

The additional lectures will be provided to existing students at no extra cost.

And if the lecture was helpful, a one-line review would be a huge source of strength. If you haven't left a review yet, I would be grateful if you could leave a short one! 🙏

👉Write a course review

🎯 For those who haven't taken the course yet

Now, we are in an era where the difference in skill is determined not by whether you use AI coding tools, but by how well you use them.

Within just 4 months of its release, more than 5,000 people have taken the course, and a wide range of individuals, including not only developers but also marketers, data analysts, students, and non-developers, are participating.

Recent Reviews

I've taken dozens of courses on Inflearn, but this course was on another level. It's absolutely insane!!
I've watched a few Claude Code-related lectures on YouTube and Inflearn, but this is the first time I've seen a course that covers everything so systematically, from the basics to the latest updates. It was really impressive how it didn't just stop at introducing features but also pointed out why things are used this way. I am confident that it will be of practical help to everyone, from those who know nothing about Vibe Coding to those who already have experience.
...
Even though I only applied a part of this course, my development speed and depth have completely changed. It's not just about coding fast; I feel like the level of design itself has improved. I truly felt like I had grown wings.

...
To be honest, it's so good that I almost want to keep it to myself, but I still highly recommend it. I will definitely buy Gym Coding's new lectures as soon as they are released. I've already purchased the Next.js and React courses as well. I would be grateful if you continue to create more lectures like this in the future!

View original review

And right now, we are having a 25% discount on all courses to celebrate reaching 5,000 students! This discount is only valid until midnight tonight. Many people contacted me saying they missed the previous discount, so I'm making sure to let you know this time.

👉Enroll now at the discounted price

Thank you! 🙇‍♂