> For the complete documentation index, see [llms.txt](https://yagi-eng.gitbook.io/resume/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yagi-eng.gitbook.io/resume/readme.md).
# Overview
### Main
| key | value |
| ------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Name | Kohei Yaginuma |
| Github | [@yagi-eng](https://github.com/yagi-eng) |
| Qiita | @yagi\_eng
Trending multiple times, Highest daily ranking: #1
※Moved to Zenn
|
| Zenn | [@yagi\_eng](https://zenn.dev/yagi_eng/books) |
| note | [@yagi\_eng](https://note.com/yagi_eng) |
| X | [@yagi\_eng](https://x.com/yagi_eng) |
### Sub
| key | value |
| ------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Wantedly | [@yagi\_eng](https://www.wantedly.com/id/yagi_eng) |
| Speaker Deck | [@yagieng](https://speakerdeck.com/yagieng) |
| Instagram | @yaginu\_travels\_around
Travel posts
@yaginu\_nakame\_lunch
Gourmet picks around Kamakura area
|
| MBTI | [INTJ](https://www.16personalities.com/ja/intj%E5%9E%8B%E3%81%AE%E6%80%A7%E6%A0%BC), but [changes frequently](https://x.com/yagi_eng/status/1948613914440106052).. |
| Favorite Languages | Go |
| Interests | AI, working at startups, building and scaling engineering organizations |
| Hobbies | Traveling abroad, muscle training, surfin, swimming, marine activities, gaming |
### Summary
I began my career in software development through a two-year internship at a startup when I was an university student. In 2017, I joined a major systems integrator as a new graduate, where I successfully led a ¥100 million (\~$1M USD) project as a project manager in my second year.
In 2019, I transitioned to freelancing. Later in 2023, I co-founded an EdTech startup and served as CTO and tech lead, where I was responsible for building and scaling the product and the engineering team. As of 2025, I’m once again working as a freelance technical advisor, supporting multiple clients with their technology and product development.
I have led development across a wide range of domains including web apps, mobile apps, dApps, and cloud infrastructure. My core strengths lie in backend development, team management, and early-stage technical leadership. I'm particularly experienced in supporting startups and new product initiatives—offering guidance on technology selection, architecture design, and project direction.
Having worked at a large enterprise with over 6,000 employees, I am also comfortable navigating cross-department collaboration and managing large-scale projects with multiple stakeholders.
In addition to client work, I also pursue personal projects and technical outreach, including:
* Developed a dApp that generates NFT art based on heart rate data
* Built a LINE bot for restaurant search (400+ registered users)
* Gave a solo tech talk in front of 120+ attendees
* Regularly publish technical articles on Qiita and Zenn (multiple trending posts, ranked #1 daily)
Recently, I've been particularly interested in generative AI, and I’m actively exploring how to apply AI agents to both workflows and product features.
If you're looking for support in software development or technical leadership, feel free to reach out.
[The detail is here](https://yagi-eng.gitbook.io/resume/)
日本語版もこちらにあります。
---
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