About
I am Valentyn Korzun, a full stack developer. Since 2021 I have built web applications at Flexum, across the whole path a request takes: the React interface, the Node.js service behind it, the database, and the cloud it runs on. Lately that path also includes AI features, which is where most of my current thinking goes.
I care about reliable delivery and code that the next person can read. In practice that means thorough code reviews, proposing the architecture before the feature, and cleaning up old code instead of building on top of it.
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Frontend
TypeScript, React, Next.js, TanStack Query, Tailwind, Redux, XState, Tiptap, CKEditor, real-time collaboration
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Backend
Node.js, NestJS, PostgreSQL, Redis, third-party services
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AI engineering
Model providers, AI SDKs, retrieval-augmented generation, evals and observability
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Agent-assisted development
Claude Code skills and plugins, MCP servers, agent-written e2e tests
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Cloud and delivery
Google Cloud, AWS, GitHub Actions, CI/CD pipelines
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Practice
Code review, TDD, architecture proposals, refactoring
Experience
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Full Stack Developer, Flexum
- Outsourced product work: different teams, different requirements, a new domain every few months.
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Full Stack Developer, BeHealthy.ai
- Supporting a health app product.
Education
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Bachelor of Software Engineering, Kherson State University