Welcome to the Demian Kostelny website!


Sure, here you can find my own services of web and blockchain development. I'm can create for you your own smart contracts with Solidity, but also I can write for you your own NFT game :)


Here you can find technologies of your dream!


As every cool web-developer, I use Vue.js for building nice front-end of web apps.


Can write smart contracts and work with Web3.


So when I want to build a new Solana program - I use Rust, Anchor, and TypeScript to do that.


I have good skills with PHP development - want to build some apps? Use PHP ✌️


I provide nice services for the development of e-commerce websites and everything that I can build with WordPress CMS.


When I want to build some cool apps with PHP, I prefer to use the Laravel framework for building all app logic and API.


My story begins in 2017 when I had programming only as a hobby, but soon this become more interesting for me that just coding some small scripts or calculators. And then I began my path as WordPress/PHP developer, and in the spring of 2018, I got my first job as a Junior WordPress developer. In that days I was a real noob 😉

Soon with more practice and time, I started becoming more and more professional in this part of my development. Today I have 3 years of experience in web development and I can say that with all projects that I created and experienced I become a Middle PHP Developer. But also I started my path in blockchain development, in this kind of development I’m not super – but I’m like a junior blockchain dev ✌️

Sometimes I like to write some articles about web development or make courses for Udemy, and I do this in my free time. It’s cool to feel that the material that you created helps someone to become a much better developer 🔥 And yeah, if you want – you can find my book “PHP Junior Kit” on Google Play Books.


But that's not all


2018 May - 2018 Oct | Morkva | Junior PHP Developer

Templates and plugins development for WordPress websites.

2018 Oct - 2019 Jan | Anvi | Wordpress Developer

Fixing bugs and updating websites/plugins that were created with WordPress.

2019 Jan - 2019 Jun | Freelance | PHP/Wordpress Developer

Apps development with Symfony and Laravel.

2019 Jun - 2020 Feb | Sovalogic | Laravel PHP Developer

Apps development with Wordpress, Laravel, Symfony, React.

2020 Feb - Now | Self Employed | Wordpress/Blockchain Developer

E-commerce development and smart contracts writing with Solidity.


For now I started making my own courses for Udemy and also soon I'm gonna upload all this on my own YouTube channel. But here is some stuff that you can find.

GraphQL - Beginner's Course 2022

May 2022 - I published my new course on Udemy and this is a small course about the main concepts of GraphQL with Node.js

Vue.js - Complete Course For Beginners

In spring of 2020 I created my own Vue.js free course for Udemy. And now I've got 10k students and 4/5 rating 🎉

PHP: Junior Kit

So, in 2018 I wanted to write my first programming book - and here it is. This is PHP Junior Book, that's is good for beginners that want to become PHP Junior Developers.

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