John Deliyiannis
About me and my blog

I build the whole thing and stay close to the work

I'm a software engineer based in Greece. I build web and mobile products from early idea to production, then write down what I learn along the way.

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The short version

Hardware first.Then the web took over.

Hey, I'm John Deliyiannis. I'm a software engineer based in Greece. I build web and mobile products from early idea to production.

I started out with hardware at university, then moved into web work while I was still a student. I began with WordPress, Joomla, HTML/CSS/JS and PHP in 2006, and moved into professional Rails work around 2010.

Most of my work has been in small teams where I had to own the full path from idea to production. I am comfortable across data modelling, backend, frontend, payments, infrastructure and deployment, but the real goal is making the product useful and stable.

Rails is my home base, but real product work is bigger than one framework. I use whatever gets the product shipped and keeps it maintainable.

2006First client sites

HTML, CSS, JavaScript, PHP and CMS work while studying.

2010Rails became home

Production applications, growing teams and more ownership across the stack.

NowProducts end-to-end

Rails, mobile apps, infrastructure and practical AI features in production.

A few highlights

What I've built

Full work history

Collaborate Healthcare

first engineer on a digital health platform for chronic-care workflows. I built and owned the stack, from data model to deployment, then helped grow the team to six. collaborate247.com

Lynx Educate

co-founded the engineering as Fractional CTO. I worked on access controls, audit logging and security policies that helped the platform through SOC 2.

DRAFA

a complete sports-venue booking product with a Rails API, React Native app, Redis-backed real-time scheduling and Stripe payments.

HTA-Hive

built RAG search and assistant flows over a large pharmaceutical document set across Rails, Angular and FastAPI.

Side projects

Side projects I ship solo for fun: DCAloop, PressureTalks, DailyAcademia, HotelData and more.

What I work with

Rails at the center. Whatever else the product needs.

Rails and Hotwire are still the core. I also ship practical LLM and RAG features that run in production.

About this blog

I write the article I wish I'd found when I was stuck.

I write about Ruby, Rails, product engineering, AI and automation. Most posts come from real problems I hit at work or in my own projects. I write the article I wish I'd found when I was stuck.

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Find me online

Want to talk about a product or a hard technical problem?

Find me on GitHub and LinkedIn, or send me an email.

[email protected]