the engineer runtime
Senior Full-Stack & AI Engineer, React, Next.js, Node.js, Python, RAG & AI Integrations, SaaS & FinTech
Dmytro Zavada, Senior Full-Stack & AI Engineer | Lead JavaScript/TypeScript Engineer. 11+ years in tech and a Master's in Computer Science. Specializing in React, Next.js, Node.js, Python, RAG, AI Integrations & Scalable Web Applications across SaaS & FinTech ($1.5M+ processed volume). Available globally. I take long-term retainers: you work with me after launch, not a two-week handoff. No agency, no juniors.
mail zavada.dmitry@gmail.commacOS · Linux · Windows · available globally · remote B2B - email, Upwork, or the form →
Dmytro Zavada
Kyiv, Ukraine
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❯ whoami
Dmytro Zavada
Senior Full-Stack AI Engineer | TypeScript | RAG, LLM & AI Integration
Senior Full Stack Developer · Jun 2017 - Present · Freelance · Ukraine
AI & RAG Engineering: OpenAI API, Anthropic, LLM integrations, Embeddings, PostgreSQL/pgvector, Vector Databases, LangChain, LlamaIndex, Vercel AI SDK, RAG pipelines, semantic & vector search, AI Agents, AI chatbots, AI assistants, knowledge bases, document Q&A, AI-driven automation, Text-to-Speech (StyleTTS2), audiobook generation
Next.js · React · Node.js · NestJS · Python · AI · RAG · Web3
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Click a row in spaces - availability and the career. I stay on the product.
11+
years of experience
$1.5M+
processed volume
Years
not sprints - long-term
100%
hands-on - no juniors
Hire me for
SaaS, Mini Apps, and AI - long-term senior execution, not an agency handoff.
Marketing and product sites on Next.js - pixel-perfect, mobile-first, Core Web Vitals as a requirement, not a later ticket.
From DB design and NestJS to polished Next.js - dashboards, marketplaces, fintech, CRM, booking, e-learning.
Mini Apps, payment bots, TWA - Next.js inside Telegram. Last shipped: a Mini App under NDA.
LLM integrations (OpenAI, Anthropic), RAG, TTS / audiobook pipelines, automation - a step in the product, not a demo chat.
I don't just write code - I build production-grade products.
Ready to get started? Send me a message - I'm available to start now. Let's discuss your project, requirements, and the best way to move forward.
With 11+ years in tech and a Master's in Computer Science, I help startups, founders, and engineering teams build production-grade web applications from scratch.
🍏 I'm passionate about AI-driven innovation and solving complex engineering challenges. I build flexible, scalable systems that are easy to maintain, extend, and grow as products evolve.
FinTech, HighLoad, $1.5M+ processed volume on live payment systems. I look for long-term retainers: I ship v1 and stay. Visiting Media for three years. Upwork product delivery since 2017 - still active. Not a two-week dump.
100% Hands-On: you work directly with me. No agency bloat, no hidden outsourcing, and no hand-offs to junior devs. You get senior-level architecture and execution on every line of code.
Full Product Ownership: from DB design and NestJS backends to polished Next.js interfaces and AI integrations. Polished React interfaces, robust backends, and modern technologies like AI and DevOps come together as one product.
Recent path: Senior Software Engineer on an NDA fintech Mini App (Aug 2025 - Sep 2026), Senior Full Stack at Visiting Media (2022-2025) and Upwork (2017-present), ETNA Network, Team Lead at Siteplus, and a Master's in Computer Sciences at the University of State Fiscal Service of Ukraine.
If you're looking for a senior full-stack engineer to join for the long run, contribute beyond code, and help build a product that lasts - message me today.
What I take on
Senior full-stack execution - from NestJS and FastAPI backends to Next.js UIs, AI agents, automation, scraping, and Web3.
Core Expertise
Senior Full Stack Engineering • React Development • Next.js Development • Node.js Development • TypeScript Development • Python Development • MERN Stack Development • SaaS Development • Product Development • Startup MVP Development • AI Integration • Generative AI • LLM Integration • RAG Development • AI Agents • AI Applications • AI Automation • Vercel AI SDK • Scalable Web Applications • Enterprise Applications • API Development • REST APIs • GraphQL • Microservices • FinTech Development • Real-Time Applications • Cloud Applications • Database Design • PostgreSQL • MongoDB • Vector Databases • Semantic Search • Full Stack AI Development • Product Engineering • Senior Software Engineering • Senior Full Stack Developer • Senior React Developer • Next.js Developer • Node.js Developer • TypeScript Developer • AI Engineer • AI Agent Developer • Product Engineer • NestJS • FastAPI • Prisma • Supabase • React Native • Docker • AWS • OpenAI API • Anthropic API • Agentic AI • MCP Server Development • Workflow Automation • HighLoad Systems • Telegram Mini Apps • Telegram Bot Development • Web3 Development • Remote Full Stack Developer • Freelance Full Stack Developer • Full Stack Developer Ukraine • Full Stack Developer Kyiv
Some client names and URLs stay off this page. The shape of the work is fair to describe: international SaaS, payments, and ops products.
Selected work
Lead AI & Full Stack Engineer · 2026
Multilingual AI Assistant with multi-provider LLM fallback (VSCode API, Gemini, OpenRouter, Groq, OpenAI), context-aware RAG knowledge lookup, SSE streaming, and automated lead capture.
Full Stack Developer · 2024-2025
Corporate website & custom admin dashboard for a medical & cosmetology center. Features an intuitive CMS control panel allowing salon staff to manage services, price lists, and content independently.
Senior Software Engineer · NDA · 2025-2026
FinTech HighLoad Web & Telegram Mini App - virtual/physical cards, $1.5M+ processed volume. Next.js, Node.js + Express + MongoDB, Playwright. Client name withheld.
Answers to common questions about working together
For a marketing site we start from the brief or Figma. For product work we start from the domain: business rules, data model, existing APIs. Then architecture, milestones, iterative delivery with updates, QA, and deploy. You work with me directly - no middle managers.
Yes. I sign a standard NDA before we discuss confidential product details or share source. Visiting Media and other client systems stay behind that line on this site.
Frontend: React, Next.js, TypeScript, React Query / Zustand / MobX / Redux, Jest / Cypress / Vitest, MUI / Tailwind. Backend: Node.js, NestJS, GraphQL / REST, Prisma, Postgres / Mongo / Supabase. Also Telegram Mini Apps, AI (OpenAI, Anthropic, RAG, TTS), and React Native when the same product needs a phone.
Send a short brief - what you need, a deadline if you have one, links or Figma. Email, LinkedIn, or Upwork. I am available to start now. Then a fixed-price estimate or an hourly start - and a retainer if you want me to stay.
Long-term is the default. I ship the first version, then stay - retainers in months and years, not a two-week dump. Visiting Media was three years. Upwork product work has run since 2017 and still does. I can start now and I plan to stay.
Yes. Remote B2B globally, including Ukrainian teams. We can agree on a contract and invoicing that fits both sides.
Architecture and MVPs that scale, performance, full-stack debugging, AI and Telegram where they earn their keep - and I stay on the product after the first deploy.
Ready to get started? Send me a message - I'm available to start now and to stay. Long-term retainers, not a two-week handoff. Let's discuss your project, requirements, and the best way to move forward.
mail zavada.dmitry@gmail.comAsk about experience or services