About
From building services to software engineering. A fairly unconventional career path.
Code and conversation, keep it simple.
kkm-horikawa
I started working in building services at 18 -- plumbing, HVAC, that sort of thing. At 20, I got hooked on programming, switched to night shifts on job sites, and attended a vocational college for two years. Classes during the day, construction at night. It was tough, but it turned me into a craftsman of a different kind -- one who writes code.
After a wide-ranging career spanning airline reservation systems, electronic medical records, and embedded development for defense products, I also taught IT courses at a major vocational college as a full-time instructor (homeroom teacher and all). During my Systems Integrator days, I mainly worked with Java and VB, but I got completely hooked on Python when I started teaching it. It had always been high on my "languages I want to learn" list but I never got around to it -- turns out the teacher learns the most. Now I work as a freelance Python/Django engineer, building things like Wagtail CMS plugins.
Whether it's a large-scale project or a solo gig, I adapt to whatever environment I'm in. I have a habit of avoiding jargon, so I can communicate well even with companies that don't have an IT department.
Backend Dev
Django / Wagtail / DRF is my home turf. I can handle most things with Python.
Infrastructure
Infrastructure as Code with AWS + Terraform. 18 custom modules and counting.
Teaching
Former vocational college instructor. I'm good at breaking down technical concepts.
Backend
Frontend / Mobile
Infrastructure
DB / DevOps
In a Nutshell
Backend is my strongest suit. I can handle most things with Python and Django. I'm also comfortable writing infrastructure with Terraform, so I can take care of everything from app to infra on my own. Frontend is more of a "capable but not my specialty" situation.
Certifications
Career
Building services -> Systems Integrator -> Education -> Freelance. Not a straight line, but it all connects.
Experience
From enterprise-scale systems to solo projects where I do everything. Versatility is my strength.
Freelance Engineer
Sole Proprietorship
Handling multiple projects in parallel with Python/Django at the core. A mix of end-to-end solo engagements and team-based work, from initial meetings through to production operations.
- Web media development (Wagtail / React / AWS) - Full-stack role
- Energy company app (PM / Django / Go / K8s) - PM & developer on a 60-person project
- Machinery manufacturer internal system (Django / Flutter) - End-to-end from proposal to operations
- Subscription automation product (Django / React) - Led development for 3 companies
In-house SE / IT Instructor
Major Vocational College
Full-time faculty member in the IT department, serving as homeroom teacher while handling classes, campus infrastructure, and school events -- a true jack of all trades.
- Taught IT courses (HTML/CSS/Python/Java/JS/System Design/Certification Prep)
- Managed network/servers across 4 campus buildings + developed internal tools + staff PC troubleshooting
- Company visits and high school outreach for tech trend insights and career advising
- Organized open campus events, sports festivals, and other school activities
Systems Integrator / Large-scale Projects
Multiple Companies
Worked on systems across various industries. In the defense sector, I even did physical network construction at military bases.
- Embedded systems development for defense products (C / Ada / ~5,000-person organization)
- Core system upgrade for a major logistics company (VB.NET / Java)
- Electronic medical records system enhancement (Java / Spring Boot / Selenium)
- Domestic travel booking web app for a major airline (Java / Spring / 100-person project)
Turning Points
Key moments in a non-linear career.
Published 5 Wagtail Plugins
2024 - 2025OSS Activity
Published plugins for Wagtail CMS on PyPI: an HTML editor, reusable blocks, an SEO toolkit, an asset publisher, and an E2E testing framework. I build what I need and put it out there.
Built AWS Infra with Terraform
2024Personal Project
Managed an AWS multi-account environment with Terraform for a personal project. Designed to be switchable between App Runner / ECS / EKS, with CloudFront + WAF, OpenTelemetry integration, and Playwright E2E tests fully set up. 18 Terraform modules in total.
Career Change: Building Services to IT
2014 - 2017Career Change
Entered the building services trade at 18. At 20, I got interested in programming, switched to night shifts, and started attending a vocational college. Two years of classes by day and construction by night. Jumped straight into a Systems Integrator career after graduation. The hands-on experience from the job site still quietly comes in handy in software development.
Services
What I can help with. I don't just build and walk away -- I stick around for operations too.
Web Application Development
Backend development is my forte, using Django / DRF / Wagtail. API design, authentication, CMS builds, and more. For the frontend, I work with React and Tailwind.
Cloud Infrastructure
Managing AWS environments as code with Terraform. From selecting between App Runner / ECS / EKS, to VPC design and CI/CD pipeline setup. Cost optimization is always on my mind.
Wagtail CMS Solutions
Site building and customization with Wagtail. Leveraging experience from developing 5 custom plugins, I create CMS environments that get the details right.
Mobile / Desktop Apps
Cross-platform development with Flutter and Flet. Combined with DRF APIs on the backend, I can build entire systems end-to-end.
Technical Consulting
Architecture reviews, code reviews, and technology selection advice. With experience ranging from large-scale projects to solo development, I can tailor recommendations to any scale.
Technical Education / Mentoring
Junior developer training backed by vocational college teaching experience. I'm good at explaining things in plain language. From training program design to hands-on workshops.
Contact
Work inquiries, technical questions, anything at all -- feel free to reach out. I used to be a career advisor, so I'm happy to chat about career paths too.
Get in Touch
Reaching out via GitHub is the most reliable way to contact me. You can also find contact info on my blog.
Location
Yokohama area, Japan
Remote work available
GitHub
Send a Message
Work inquiries, technical questions, or anything else -- feel free to drop a line.