In a world where every résumé looks similar, “differentiation” gets you hired. Over six weeks, learn four practical résumé strategies directly from a backend professional.
816 learners
Level Basic
Course period Unlimited
Reviews from Early Learners
5.0
신영인
Thank you so much for this excellent course! This is a course I simply had to leave a review for! As you go through the lectures, you can really feel how much care went into everything from the structure to the analogies and examples. I'm a self-taught developer currently running a service on my own. I had no idea what I was lacking or what I needed to learn more about, when I came across DingCodingCo's videos on YouTube and started considering taking the course. I hesitated a lot before purchasing. Since I was already working in the field, I was worried it might all be things I already knew. But as I listened to the lectures, I actually came to think it was really the right decision. It felt like DingCodingCo was putting names to the issues I'd encountered in my work and the processes I'd gone through solving them on my own. The parts I knew and didn't know became clearly defined, and as a result, I came to understand well what I need to pay more attention to and study. I also got many ideas about what to improve in my service! I think this is a course worth taking even if you're not a job seeker, as long as you're running a service! Thank you so much for this great course!
5.0
고양이
As a backend developer, I had been feeling that when updating my resume, it's important to show specific competencies connected to practical experience rather than simply listing technologies. This course was a great help in supplementing those areas. Thanks to the real-world cases and project-based explanations covered in the course, instead of simply writing "Java backend capable" on my resume, I was able to more clearly include how I actually utilized it in real situations and what problems I can solve. In particular, I was able to gain specific examples and thought processes that can be used during interviews, so I think this is a course that provided a clear direction for the overall job preparation process.
5.0
심야공방
Simple. Without even an introduction like "Here's what you can learn," it dives straight into the practical aspects of what to write on a resume to make interviewers nod in approval. I work as a backend developer for member/authentication services. Since I mostly deal with hardware and infrastructure directly in on-premise environments, I used to skip courses with 'cloud-based practicals,' thinking, "This is different from my environment." This course also has a part dealing with AWS EC2 and RDS using Terraform, but oddly, I didn't feel any resistance. This is thanks to the way Terraform was introduced simply, almost like a bash script, focusing on "why use this" and "how to collect performance improvement metrics through this." The flow of the lecture itself is organized as: 'Why is it needed → How to configure it → What's needed to prove it with numbers' This structure means it's not just a simple infrastructure practical, but it allows you to write something like "derived improvement plans based on performance metrics" in a single line on your resume. I actually operate an authentication system in an on-premise rack environment full of physical servers. It's an environment where there are physical units for Web01, Web02, ARS, Staging, and DB backup equipment. Even in such an environment, the Prometheus, Grafana, CloudWatch metric design, and load testing → improvement cycle explained in this course were directly applicable. Whether it was cloud or on-premise didn't matter in this course. At first, I thought the Week 3 index optimization lecture would be at the level of basic DB fundamentals. But it actually corrects your perspective on reading execution plans and tracing bottlenecks. It clarifies the meaning of Covering Index, not just at the level of "it's fast," but precisely points out its location in the overall tuning strategy and I/O cost reduction. I also had an experience tuning an identity verification history API where I simply tried to shorten the query length. Following the lecture, I was immediately able to catch on, "Ah, this was a case where the range index condition wasn't applied." That kind of intuition can only be gained from a lecture that explains things centered around cases. I am also looking forward to the subsequent lectures on transactions, lock strategies, and code optimization. This course doesn't just deliver practical knowledge. It is the only course that guides you on "how to write that experience on your resume." So, I changed items that I used to just write like "Automated settlement batch process and improved statistical processing system" on my resume, to reflect the quantitative performance expression, problem-solving oriented structure, and flow demonstrating the meaning of structural transformation I learned in the course, as follows: - Due to the Oracle procedure + Excel-based statistical system, monthly average of 14 million rows of self-authentication transaction data required manual processing taking over 2 hours, with constant risk of work conflicts and human error. - Built an E2E automated batch system based on Spring Scheduled + Crontab. - Prevented parallel execution conflicts and made execution cycles flexible with Crontab. - Included automation of report generation based on Apache POI + automatic sending to administrator email. - Processing time reduced from 2 hours → 15 minutes (88% reduction), maintained 0% settlement error rate, and improved speed of decision-making for related departments with automated reports. Since then, I have gained a standard for judging which structures are stable in practice and which designs are advantageous for maintenance. This standard is immediately integrating into my resume and way of thinking. It's not just a skill upgrade, but a change in the ability to articulate my competence. This course is 'a course that enables me to talk about what I did as a backend developer.' Even if it's not cloud, even if it's not the latest technology, It is a must-take course for any developer who wants to change the sentences on their resume.
Essential backend problem-solving experience
Spring Application Optimization
Experience with Index and Transaction Issues
Redis Fundamentals and Troubleshooting Experience
From monitoring concepts to actual AWS setup
If you've learned all of this, why does your résumé keep getting rejected?
Because you haven't been able to showcase core technologies such as database indexing, transactions, server optimization, and Redis as problem-solving experience
on your résumé as a backend developer.
❓ DB indexing: How did you speed up slow queries, and can you show the results with numbers?
❓Transaction: How did you resolve concurrency issues or bottlenecks?
❓Server optimization: What specific process did you follow to achieve high performance with minimal resources?
❓Redis: Have you ever dramatically improved processing speed by leveraging a cache?
If you can't provide clear answers to these four questions,
Even before entering the interview room,
only applicants who have sufficiently answered these questions in their résumés can pass the initial screening and succeed in the interview.
Now, become a competitive backend developer who clearly demonstrates "Problem → Solution → Result"!
2026/03/08
Passed the document screening at Toss, Karrot, Buzzvil, Channel Corporation, and Today's House ***님
2026/01/03 Hyundai AutoEver server developer final acceptance
Toss, Korean Air, Hyundai Capital, ConnectWave, ESTsoft, and AhnLab document screening pass ***님
2025/10/04 Toss Bank Server Developer Application Passed ***-nim
2025/11/14 Final acceptance as a senior server developer at Musinsa, I**님
2025/05/24 Passed the resume screening, Mr./Ms. Jeong**
2025/07/31 Final acceptance at three companies, Mr./Ms. Ohxx
Mission submissions through challenges (100+)
Do Gi-heon's tech blog link (https://dockerel.tistory.com)
Lee x-won
Backend concepts understood through real-life examples
Meal Kits, Docker, and Hiring Process Filter Overhead
Adult Comics and the Library Librarian Optimizer
Optimistic and pessimistic locks for bathroom toilets
Analogies and explanations you’ll never forget once you hear them
A beginner-friendly course
Explain why we are learning this in the first place.
Example code and test code are provided for every concept.
Explains everything from the fundamentals, including code automation, CI/CD, and the practical deployment workflow.
Textbook materials covering 946 pages provided
Preparation for real-world interviews
DB index B-Tree structure, covering index preparation
Transaction isolation levels, MVCC, and event publishing 대비
Server optimization, JPA and the N+1 problem, bulk operations 대비
Redis TTL strategies, cache invalidation strategies comparison
A practical curriculum you can apply directly to your projects
Not just learning simple concepts, but based on problem-solving cases
Built around performance issues encountered in real-world domains.
Directly usable in your resume through before-and-after improvement metrics
I have analyzed hundreds of resumes that have successfully passed screening.
Those resumes clearly shared a common characteristic.
Specifically, they described their experience solving problems in concrete terms and proved the results with numbers.
But the advice to “quantify it” feels abstract and hard to relate to, doesn’t it? I felt the same way.
So I organized it in detail and turned it into a course.
It took 178 days to develop, with a 946-page textbook, 32 hours of raw footage, and 12,665 lines of code.
The content is structured systematically so you can save time and learn as efficiently as possible.
After two thorough rounds of review, I turned the result into fully captioned course videos.
You can take all of this away in just 20 hours..
This course is not just theory. It is structured around applying identifying problems → gaining problem-solving experience → documenting your achievements with metrics to your projects, helping you create a truly competitive résumé.
We will transform your résumé from a simple introduction into a competitive weapon.
The first student to take this course was a developer from a non-major bootcamp.
Therefore, every concept is explained starting with "why do we learn this".
Docker, AWS, Redis
Isolation Level, MVCC, Query Plans, Deadlocks, Phantom Reads, Gap Locks
Transaction propagation, Thread Pool, Cache Avalanche …
We explain these concepts using analogies, practical code, and test code so that even “people hearing them for the first time” can understand them
.
Rather than simply defining terms, we also explain why each technology emerged to solve a problem.
View the Developer Job-Seeking RPG
The advice “Quantify it on your resume!” is something
you’ve probably heard many times, but most people don’t actually know how to write it.
So in this course,
A. Problem → B. Solution → C. Improvement Metrics
This flow is designed for repeated practice in a template format.
You can learn a persuasive sentence structure based on quantifiable results in this course. trong khóa học này.
Real resume problem-solving cases explained in the course
A course that just throws concepts at you and ends there,
or one where you can't even tell how they connect to real-world work…
I hated courses like that the most.
This course connects concepts → problem scenarios → real-world application.
Rather than simply explaining things,
it helps you understand them well enough to explain them to someone else..
Even 80% of the questions from a major company (one of Korea’s top tech companies)’s
technical interview course could be covered with this one course.
This is evidence that real companies look at problem-solving cases. xem xét những trường hợp giải quyết vấn đề.
Complex AWS configuration
Repetitive codebase
Deployment environment setup
I've taken care of all the grunt work.
You just take away the insights.
GitHub Actions CI/CD Automation Setup
Automated AWS infrastructure setup
Each week, you will be given a mission to apply directly to your project.
This course goes beyond simply learning theoretical concepts;
it is designed to help you develop practical skills by applying them directly to your own projects.
Additionally, for the missions you submit,
I will personally review your work and provide specific feedback.
This is a thoroughly prepared curriculum designed to help you apply the concepts you’ve learned to real-world projects and develop practical skills
.
This is not a course where you simply listen;
take away the experience of applying what you learn, receiving feedback, and growing.
->
The mission and feedback features have been moved to be provided in the Challenge course (updated as of 2025.8.26 )
For those who previously enrolled, we will provide instructions on how to transfer into the Challenge course, so please take note.
I've written a backend resume, but I don't know where I'm getting rejected.
✔ Those who have listed their skills but don't feel competitive
✔ Those who don't know the difference between a resume that gets them hired and their own resume
I have a portfolio, but I don't know how to structure the sentences.
✔ Those who only write feature-listing sentences such as “Implemented a login API”
✔ Those who want to incorporate real problem-solving experience into their resume
I want to prepare for interviews while improving my resume at the same time.
✔ Those who want to prepare for technical interviews based on their resume
✔Transactions, indexes, and Redis
Those who want to apply them to their projects
I can’t say that simply taking this course guarantees you’ll get hired by one of the top tech companies.
As more and more students see the problem-solving case studies I’ve prepared over time,
it may become increasingly difficult to stand out by simply using those cases as your own.
So I won’t make the exaggerated promise that “anyone can definitely pass.”
However, there is something you can definitely take away from this course.
Specifically, it is the ability to identify problems on your own and compellingly organize your experience solving them.
This course is not a passive lecture that simply drills specific keywords into you.
It focuses on the process of creating a resume that proves you are a developer who knows how to solve problems..
We hope this course helps you grow into a developer who thinks and grows independently.
This course is not an encyclopedic course that explains every technology from A to Z.
It focuses on accurately understanding the core concepts needed for problem-solving and
how to apply them in real-world domain situations.cách áp dụng chúng trong các tình huống thực tế của lĩnh vực.
For example, it does not explain every AWS feature. Nor does it cover Docker from start to finish.
However, the core topics of this course—
DB indexes / transactions / server optimization / Redis—are covered
in enough depth to prepare you even for interview questions.
In other words, this is a hands-on course focused on solving problems encountered in real-world projects and incorporating that experience into your resume.
If you need to explore the technology in greater depth, you will need to expand your studies separately afterward.
I will accompany you only up to that starting point.
The course is not inexpensive. I understand that the price may be a significant burden, especially for job seekers.
That is why I put the content together with a strong sense of responsibility.
I carefully considered which topics are most essential for backend developers at this point in time.
I also thought extensively about how to create a compelling résumé based on successful résumés and questions actually asked in technical interviews.
We designed it to reduce the trial and error that could take months on your own and
help you find a clear direction with a single investment.
This course is a guide based on passing experience rather than knowledge,
designed to help you revise your résumé and prepare for interviews in practice.
I would appreciate it if you viewed this not as ‘simply taking a course,’
but as ‘an investment in properly designing my career.’
I have prepared it with everything included so that I can live up to those expectations.
There is a special benefit available exclusively to those who take the course.
We have compiled technical interview questions that have actually been asked by major companies..
You can think of this as a very special problem set prepared by those who passed the resume screening to prepare for technical interviews.
This problem set will be continuously updated, so you’ll be able to prepare for interviews in line with the latest trends!!
(This workbook will be provided as a Notion page via a link!)
Claim it after verifying your course review in the community!
(I’ve written how to verify it in the very last lecture __)
That's not all
We’ll also provide a guide to preparing for a developer job (resume, portfolio, and more)!
After completing the course, the first 10 people to pass the document screening are invited to share their course reviews and application success stories in the open chat room!
As a token of our appreciation, we are sending out Starbucks gift cards.
Through KakaoTalk Plus Friend
🎟 We will send you a discount coupon 🎟
(Mobile access available, 15% off, cannot be combined with other discounts)
Free 3-month access to IntelliJ IDE!
With our support for your development studies, we have prepared special benefits through our collaboration with JetBrains.
Using the promotion code below, you can use IntelliJ for free for three months!
✅ Promotional code: HYUNJOONPARKxJB
✅ Benefit: A 3-month free trial for one JetBrains IDE (e.g., IntelliJ, PyCharm, WebStorm, etc.)
✅ Valid until: ~ December 31, 2026
✅ How to use😀😀
1. Go to the official JetBrains coupon redemption page.
2. Enter the code and select the IDE you want
3. Check the license issued via email
⚠ Notice:
This code is only available to new users using JetBrains for the first time.
(Only those with no history of using a paid JetBrains license can register.)
(You can do this indefinitely by creating new Google email accounts.)
Added a guide for cases where the Docker image breaks, feat. Anfield
Why is our database in a public subnet? Added a section feat. Hi
Added an explanation of how to install the JMH plugin feat. kongminoo
Added an explanation of index data flow feat. Moging
Added an explanation of the criteria for determining the driving and driven tables in the execution plan. feat. cho766
2-7 Added Q&A content related to Spring configuration, feat. Chunsiki
6-12. Changes to the Redis SETNX-related content, feat. happyrichman
Sharing the behind-the-scenes story of making it to the final interviews at Coupang and Yanolja — A sixth-year developer’s story of changing jobs at 24 companies [ep 5]
Dingcodingco (main instructor)
2021 ~ 2022: S Coding Club Algorithms (data-structure) Tutor
2022 ~ : Runs the coding YouTube channel DingCodingCo (with a variety of content related to developer job hunting)
2022 ~ 2023: Viva Republica Server Developer
Never give up on a student 🦈
Operating a developer employment community and organizing offline meetups
✅ Join the KakaoTalk chat: https://open.kakao.com/o/gPI6kTUg
✅ Join Discord: https://discord.gg/X74q5Yw3Sv
Dungka (Teaching Assistant)
Developers at Naver, Kakao, Line, Coupang, and Danggeun Market
If!! you have even the slightest hesitation before enrolling.
Is this the right course for me to take right now?? If you're wondering, feel free to contact us anytime via the KakaoTalk channel!!
😍 I’ll do my best to answer your questions 😍
We use IntelliJ. The Community (free) version works just fine.
Windows or Mac—it makes no difference! We provide installation instructions for each operating system.
Everything is shared via Notion and PDF!
We will share the project code!
0-1. We recommend assessing your backend résumé through a test before taking the course
Those who have run bootRun with Spring
Those who have learned Java before
Those with MySQL CRUD experience (It's okay if you don't know it. Here are free database training materials!)
Who is this course right for?
Bootcamp graduate
Spring backend experienced developer
Need to know before starting?
Backend
Spring
Inflearn Verified
Career Verified
20,995
Learners
2,105
Reviews
372
Answers
4.9
Rating
31
Courses
Park Hyun-jun · Dingcoding Co.
POSTECH Graduate · Backend Development Experience at Toss · Inflearn Instructor
20,000+ cumulative Inflearn students · 2,000+ course reviews · 4.9 rating
I explain everything simply, from why it’s needed to how it’s actually used on screen. Starting where beginners typically get stuck, I show you the process of building, clicking through, and fixing things yourself. In this challenge as well, leave the code and diagrams to Codex, and focus on judging the game’s rules and outcomes.
Inflearn Interview: https://www.inflearn.com/pages/interviewdingco
All
80 lectures ∙ (22hr 28min)
All
214 reviews
5.0
214 reviews
Reviews 1
∙
Average Rating 5.0
5
I got to know you, Dingcodingko, from Threads, moved to YouTube, and was so drawn to your incredible teaching skills that I ended up purchasing your course on Inflearn. I am a junior developer who is preparing for employment. The job market is very difficult these days, and consequently, the requirements for new graduates are increasingly high, leading to a lot of concerns as I prepare my resume and portfolio (projects). I am confident that this lecture will be able to address those concerns. Thank you for creating such good content and lectures, and I will always support you!!!
Thank you so much for following me all the way from Threads to YouTube and Inflearn. As the entry-level job market is not easy these days, I sincerely hope this course provides practical help in preparing your resume.
Reviews 2
∙
Average Rating 5.0
5
Simple. Without even an introduction like "Here's what you can learn," it dives straight into the practical aspects of what to write on a resume to make interviewers nod in approval. I work as a backend developer for member/authentication services. Since I mostly deal with hardware and infrastructure directly in on-premise environments, I used to skip courses with 'cloud-based practicals,' thinking, "This is different from my environment." This course also has a part dealing with AWS EC2 and RDS using Terraform, but oddly, I didn't feel any resistance. This is thanks to the way Terraform was introduced simply, almost like a bash script, focusing on "why use this" and "how to collect performance improvement metrics through this." The flow of the lecture itself is organized as: 'Why is it needed → How to configure it → What's needed to prove it with numbers' This structure means it's not just a simple infrastructure practical, but it allows you to write something like "derived improvement plans based on performance metrics" in a single line on your resume. I actually operate an authentication system in an on-premise rack environment full of physical servers. It's an environment where there are physical units for Web01, Web02, ARS, Staging, and DB backup equipment. Even in such an environment, the Prometheus, Grafana, CloudWatch metric design, and load testing → improvement cycle explained in this course were directly applicable. Whether it was cloud or on-premise didn't matter in this course. At first, I thought the Week 3 index optimization lecture would be at the level of basic DB fundamentals. But it actually corrects your perspective on reading execution plans and tracing bottlenecks. It clarifies the meaning of Covering Index, not just at the level of "it's fast," but precisely points out its location in the overall tuning strategy and I/O cost reduction. I also had an experience tuning an identity verification history API where I simply tried to shorten the query length. Following the lecture, I was immediately able to catch on, "Ah, this was a case where the range index condition wasn't applied." That kind of intuition can only be gained from a lecture that explains things centered around cases. I am also looking forward to the subsequent lectures on transactions, lock strategies, and code optimization. This course doesn't just deliver practical knowledge. It is the only course that guides you on "how to write that experience on your resume." So, I changed items that I used to just write like "Automated settlement batch process and improved statistical processing system" on my resume, to reflect the quantitative performance expression, problem-solving oriented structure, and flow demonstrating the meaning of structural transformation I learned in the course, as follows: - Due to the Oracle procedure + Excel-based statistical system, monthly average of 14 million rows of self-authentication transaction data required manual processing taking over 2 hours, with constant risk of work conflicts and human error. - Built an E2E automated batch system based on Spring Scheduled + Crontab. - Prevented parallel execution conflicts and made execution cycles flexible with Crontab. - Included automation of report generation based on Apache POI + automatic sending to administrator email. - Processing time reduced from 2 hours → 15 minutes (88% reduction), maintained 0% settlement error rate, and improved speed of decision-making for related departments with automated reports. Since then, I have gained a standard for judging which structures are stable in practice and which designs are advantageous for maintenance. This standard is immediately integrating into my resume and way of thinking. It's not just a skill upgrade, but a change in the ability to articulate my competence. This course is 'a course that enables me to talk about what I did as a backend developer.' Even if it's not cloud, even if it's not the latest technology, It is a must-take course for any developer who wants to change the sentences on their resume.
Reviews 1
∙
Average Rating 5.0
5
This lecture was like a sweet rain for me, as I had only ever focused on studying development and didn't know how to write a resume. My previous resume was just a simple list of stacks, project experiences, and tasks I contributed to. I wasn't satisfied with it, and although I found information saying it's good to include metrics and problem-solving processes, I felt lost because I didn't know how to actually do it. At that moment, this lecture quenched my thirst. It didn't just say "do it this way"; it clearly explained why it's necessary, what methods to use, and what kind of results can be achieved in an easy-to-understand way. Thank you!
It makes me feel that creating this lecture was worthwhile to hear that you understood the connection between 'why it is needed, how to do it, and what results can be achieved.' I hope your uncertainty about writing a resume has been resolved, and I hope the remaining lectures will be helpful to you as well.
Reviews 1
∙
Average Rating 5.0
5
Thank you so much for such an excellent lecture!! I especially learned analysis methods for DB performance improvement that I had never thought of before! If I hadn't taken this lecture, I think I would have remained trapped in the misconception that performance improvement could only be solved at the application code level... Based on what I've learned, I'll create a satisfying resume and definitely get it confirmed! Thank you
I am truly glad that you gained a perspective on improving DB performance that goes beyond the code level. I hope you incorporate what you've learned into your resume effectively, and I'm rooting for you to achieve great results!
Reviews 3
∙
Average Rating 5.0
5
As mentioned in the intro, it's not just about injecting knowledge, but explaining well from the perspective of "why" - why it's needed, and what content makes a backend developer's resume attractive. Actually, if it were just explaining up to this point, I wouldn't think there's a need to take the course, but since we even get to practice firsthand how to create content for a resume (how to quantify it), I think I can apply it when refactoring previous projects or developing new projects in the future. Thank you for creating this course, especially with the difficult job market situation!
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