Next.js specialists
Next.js App Router introduces server component paradigms that require deep understanding of caching layers, streaming, and client-server boundaries.
Audit server vs client component splits, fetch cache tags, and dynamic rendering flags.
Eliminate SSR hydration mismatches, browser API leaks, and server action timeouts.
Optimize font loading, image sizes, and bundle splits to achieve 90+ Lighthouse score.
Next.js caches aggressively at several layers, and the majority of confusing behaviour — stale data, changes that do not appear, differences between local and production — comes from one of those layers rather than from the code being wrong.
The diagnostic question is which layer: the fetch cache, the full route cache, the router cache in the browser, or a CDN in front of everything. They fail in similar ways and are fixed differently.
The error text is famously unhelpful, but the underlying reasons are few.
The second large category is work placed on the wrong side of the boundary: a component marked as client-side pulling in server-only code, or a server component being handed something that cannot cross the boundary.
These usually appear as build failures rather than runtime ones, which is fortunate. The fix is normally moving the boundary rather than adding directives until the error goes away.
Slow pages are more often slow queries than slow rendering. Before optimising bundles or images, find out how long the data fetching takes, because that is frequently the whole number.
When it genuinely is the frontend, the wins are almost always the same three: fonts, images, and a large dependency that could be loaded on demand.
Almost always caching. Local development disables most of the caching layers that production enables, so stale data and missing updates appear only once deployed.
Rarely. Most App Router problems are configuration and boundary issues rather than framework defects, and upgrading mid-incident adds risk without addressing the cause.
Khmelnytskyi, Ukraine
Full-Stack Developer — Websites, Apps, Servers, Databases, AI, SEO & QA
Full-stack developer working across the entire stack — websites, apps, servers, databases, AI integrations, SEO, and QA. Languages & Core: writes code in JavaScript, TypeScript, Python, PHP, Go, and Rust. Architects scalable systems for large-scale projects. Frontend & Interfaces: builds websites and web applications with React and Next.js. Crafts responsive interfaces with Tailwind CSS, Radix UI and Shadcn, adds smooth animations with Framer Motion, and interactive charts with Recharts. SEO Audit & On-Page Optimization: semantic keyword research, resolving technical indexing issues, and optimizing page load speeds. Structures page architecture, meta tags, and multi-language support (i18n). Copywriting & Content Strategy: writes technical articles, drafts precise content briefs for writers, and develops content plans. QA & Testing: full-cycle testing for websites, web services, and Android apps — manual QA for UI/UX and business logic, plus automated testing with Jest, Vitest, Playwright and E2E. Backend, Cloud & Databases: complex API integrations of any scale. Builds servers with Node.js (Express, Fastify). Works with PostgreSQL, MySQL and MongoDB, ORMs (Prisma, Drizzle), and cloud infrastructure (Supabase, Firebase, Cloudflare). Browser Extensions & Automation: develops Manifest V3 browser extensions for Chrome, Edge, Firefox and other browsers. Builds web scrapers for complex data extraction using Puppeteer and Playwright. AI & Intelligent Agents: builds custom AI agents and integrates LLMs from OpenAI, Google Gemini, and Anthropic Claude via API, including Claude Code setups. Servers & DevOps: Linux (Ubuntu) and VPS administration — setup, updates, real-time monitoring, secure process isolation, Nginx, PM2, and CI/CD deployment via GitHub Actions. Telegram Bots: develops advanced Telegram bots (Telegraf, Grammy) integrated with AI, payment gateways, Google Sheets, and crypto exchanges. Desktop Applications: builds cross-platform software for Windows and macOS using Electron and Rust. Additional expertise: site development and customization with WordPress and Astro.
AI & Distributed Systems Architect | Enterprise AI, RAG, Cloud, Blockchain | Advisory & Fractional Leadership
AI and distributed systems architect providing advisory and fractional leadership on enterprise AI, RAG pipelines, cloud architecture and blockchain-backed data systems.