Strelkov.NET

About

I have been building software since 2000

The languages changed — Delphi, C#, PHP, Java, JavaScript, Python. The job stayed the same: understand what the business needs, build the simplest thing that does it well, and keep it running.

I am Konstantin Strelkov, a software engineer from Ukraine, based in Barcelona.

I wrote my first production code at a steel plant in Kryvyi Rih, in Delphi and FoxPro. Since then I have built hotel and restaurant systems, mobile software for Windows Mobile and early Android, high-traffic consumer websites, software for medical equipment, an HR product, and a large fashion e-commerce platform. Today I work as a senior software engineer in ad tech.

That range is what I bring to clients. I have seen what a system looks like after ten years in production, which shortcuts come back as invoices, and which "boring" decisions keep a business running. It is also why I am careful with AI: I use it where it measurably helps, and say so when it does not.

Strelkov.NET is where I take on independent work — development, AI integration, consulting, and maintenance — and where I publish my own products.

Experience

26 years, eight chapters

Each one added something I still use.

Time in software live

Time in software: 26y 8m 25d

  1. 2022

    Ad tech

    Python developer on advertising platform services, with Angular on the front end and a broad platform stack: Docker, Mesos and Marathon, Prometheus, Temporal.

  2. 2016

    E-commerce in Europe

    Ciklum, Spain: PHP and Laravel on a fashion e-commerce platform — design patterns, clean code, Vue.js, microservices on AWS.

  3. 2013

    Product engineering

    Ciklum, Dnipro: full-stack on an HR product — UI in React, Node.js and Socket.IO, MongoDB and MySQL.

  4. 2012

    Medical equipment software

    DAXX: legacy PHP for a maker of laboratory instruments, a large migration, PostgreSQL.

  5. 2008

    Web at scale

    Cupid plc: high-traffic consumer platforms under heavy data load, with face recognition in production — CakePHP, Zend Framework, Yii, Sphinx, Memcached.

  6. 2006

    Independent developer

    Mobile automation for field staff: Windows Mobile, C#, early Android in Java, synchronised with back-office databases.

  7. 2001

    Business systems

    Hotel Bratislava: accounting and operations systems for a hotel and restaurant, plus the network they ran on.

  8. 2000

    Industrial software

    Software engineer at the Kryvorizhstal steel plant: Delphi, FoxPro, dBase.

Toolbox

What I work with

  • Back-end

    Python, PHP (Laravel, Yii), Java, Node.js. MySQL, PostgreSQL, MongoDB, Redis.

  • Front-end

    Vue.js, React, Angular, TypeScript, modern CSS — interfaces that stay fast as they grow.

  • AI and infrastructure

    Language-model integrations, retrieval, agents and evaluation. Docker, Mesos and Marathon, Temporal, Prometheus, AWS, Linux.

Let us talk about your project

Write in English, Spanish, Russian, or Ukrainian.

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