My name is Vadym Kharovyuk. I am a Java Backend developer from Kharkiv with five years of experience in the Spring ecosystem. During this time, I have progressed from simple REST APIs to production products with AI integrations, PWA, and microservice architecture.

In parallel with commercial projects, I maintain a technical blog webscraft.org/blog — I write about real-world cases from my own experience, not just a rehash of documentation.

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🎯 About Me

32 years old, Kharkiv, Ukraine. I came to IT consciously — after university, I realized I wanted to build products, not just write code according to technical specifications. The first years were monolithic Spring Boot applications, databases, REST APIs. Then came microservices, message queues, AI integrations.

Today, my main specialization is the full cycle of Backend development: from architecture design to production deployment with monitoring and support. In parallel, I am developing my own SaaS product and maintaining a blog where I share technical solutions from real projects.

The best way to understand a technology is to build something real with it and bring it to production.

🚀 One of the projects: Kazki AI

Kazki AI — a service for personalized audio fairy tales for children, where the child is the main character of the story. Parents enter the child's name, interests, and favorite characters — the system generates a unique fairy tale and voices it using an AI voice via ElevenLabs.

The project was written entirely independently — from architecture to deployment. It's not a pet project for a resume, but a live production service with a payment system, subscriptions, push notifications on iOS and Android and real users.

What's inside:

  • AI content generation — OpenAI generates the fairy tale text considering the child's name and preferences, ElevenLabs voices the result with a natural voice
  • Payment system — Stripe with a subscription model: various tariff plans, access management, webhook event processing
  • PWA without App Store — home screen installation, offline mode, push notifications via Web Push API (VAPID) on iOS 16.4+ and Android
  • Authorization — Spring Security + OAuth2 (Google), CSRF protection, session management via Redis
  • SEO and performance — server-side rendering via Thymeleaf, Redis-level caching, image optimization via Cloudinary
  • Database — PostgreSQL with a well-designed schema: users, fairy tales, subscriptions, push subscriptions, payment events

The entire stack — Spring Boot, PostgreSQL, Redis, ElevenLabs, Stripe, Cloudinary, PWA — is deployed and maintained in production by one person.

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🛠️ Technology Stack

Backend — main specialization

  • Java 17/21 — main language
  • Spring Boot — production applications of any complexity
  • Spring Security — authentication, OAuth2, JWT, CSRF
  • Spring Data JPA / Hibernate — working with relational databases
  • Spring MVC / REST API — building HTTP interfaces
  • Spring Cloud — microservice patterns

Databases

  • PostgreSQL — main relational database for production projects
  • MySQL — alternative for certain types of projects
  • Redis — caching, sessions, queues

Message Queues and Asynchronicity

  • Apache Kafka — stream data processing, event-driven architecture
  • RabbitMQ — asynchronous queues for microservices

Frontend and PWA

  • Thymeleaf — server-side rendering with SEO
  • JavaScript, HTML, CSS, Tailwind
  • PWA (Service Worker, Web App Manifest)
  • Web Push API / VAPID — push notifications on iOS and Android
  • Badging API — counters on PWA icon

AI and External Integrations

  • ElevenLabs — speech generation (Text-to-Speech)
  • OpenAI API — text content generation
  • Stripe — payment integrations
  • Cloudinary — media storage and image optimization

DevOps and Infrastructure

  • Docker — containerization
  • Railway / Render — deployment of production applications
  • GitHub Actions — CI/CD pipelines

💼 What I do for clients

Over five years of commercial development, I have developed an approach that works equally well for early-stage startups and mature businesses with legacy systems.

I start with architecture, not code

Before writing the first line, we analyze the business problem, identify potential bottlenecks, and choose the stack for the specific case. Monolithic Spring Boot or microservices — it depends on the scale and team, not on trends.

Full cycle without gaps

Database design, REST API, authorization, integrations with payment systems and external services, deployment, monitoring. The client receives a finished product, not a set of components that still need to be assembled.

Performance built-in from the start

Redis caching, SQL query optimization, asynchronous processing of heavy operations via queues — all of this is laid into the architecture immediately, not added as "optimization" after the system crashes under load.

Maintainable code

The code I deliver is readable a year later without the author present. Documentation, clear package structure, test coverage for critical paths. Because maintaining the project after launch will fall to you or another developer.

Portfolio of works — webscraft.org/portfolio

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📝 Technical Blog

Together with the team, we maintain a technical blog webscraft.org/blog — we write about real development cases, new tools, and approaches that we use in practice. Not a rehash of documentation, but concrete solutions from live projects.

If you have a technical question, want to discuss project architecture or simply don't know where to start — write directly, I respond personally.

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🎯 Development Approach

Over five years, I've seen the same problems in different projects. Not technical ones — organizational. Development starts without a clear architecture, the first release comes out later than planned, and then half the time goes into refactoring instead of new features. My approach is built around preventing this.

Problem: "let's do it first, then figure it out"

The most common situation is a project starting without database and architecture design. Three months later, it turns out that the schema cannot handle real data, and adding a new feature means rewriting half the code. I always start with data modeling and defining system boundaries — even if the client wants to "just launch quickly".

Problem: microservices for the sake of microservices

A team of two people builds a distributed system with five services, Kafka, and separate databases — because "that's the right way." As a result, 90% of the time goes into infrastructure, not the product. For an early-stage startup, a well-written monolith on Spring Boot — is often the more correct solution. Microservices appear when there is a real need, not from day one.

Problem: performance as an afterthought

"First, let's make it work, then optimize" — a classic that costs dearly. N+1 queries in Hibernate, lack of indexes, lack of caching — all of this is easily solved at the architecture stage and very difficult to fix in production under load. Redis, correct indexes, asynchronous processing of heavy operations — I lay this foundation immediately.

Problem: code only the author understands

A year later, the developer who wrote the system no longer works at the company. A new developer spends weeks trying to understand what's going on. Readable code, clear structure, documentation of critical decisions — this is not about perfectionism, it's about the cost of maintenance.

Good architecture is not one that looks beautiful on a diagram, but one that is easy to change when business requirements change.

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❓ FAQ

What is your main specialization?

Java Backend in the Spring Boot ecosystem. Additionally — PWA, Web Push, AI integrations (ElevenLabs, OpenAI), payment systems (Stripe).

Do you take on commercial projects?

Yes. I consider Backend development, technical consulting, and full-cycle web product development. Contact me to discuss details.

How much does development cost?

Depends on complexity. A simple REST API — from $200, a full-fledged product with authorization, payments, and PWA — from $1000. I always provide a detailed estimate after analyzing the requirements.

Are there examples of live products?

Yes — Kazki AI and this website webscraft.org are built on the same stack that I offer to clients.

Where can I see the code?

github.com/VadimKharovyuk

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📬 Contacts

If you have a project or questions — write: