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Open to new architecture & product roles

Denis Klymenko

I turn complex business problems into production platforms.
Architecture, code, AI, delivery - one person.

> building full-stack products...
> developing production-ready AI agents...
> connecting product goals with technical reality...
> from concept to scale.
20+
Projects Delivered
14 built from scratch
3
AI Systems in Prod
agent, moderation, content pipeline
5
Live Products
maintained & scaled solo
9+
Years of Experience
full-stack, product & AI

Featured Projects

Real products and AI systems built to scale, operate reliably, and actually solve business problems.

Enterprise AI Agent for love💗epil

Built from scratch

A production AI consultant for a European beauty chain. Built with strict business control and full observability.

Ownership & Delivery

  • •Built a custom AI orchestration engine with 21 tools covering bookings, FAQs, and support handoffs
  • •Set up a fine-tuned GPT-4.1 Mini pipeline with automated validation, auditing, and quality checks
  • •Integrated Langfuse + OpenTelemetry tracing so we can track every tool call and token cost
  • •Added semantic search using pgvector for FAQs, locations, and service details
  • •Deployed the agent across the website and messengers with shared memory and seamless operator handoff

Client Results

  • ✓Live in production across 18 studios in 5 countries
  • ✓Stable production behavior through tool-level validation and controlled flows
  • ✓4 delivery channels: Website, Telegram, Instagram, Facebook

Technologies

OpenAI GPT-4.1 MiniVercel AI SDKLangfusepgvectorNext.js 16PrismaPostgreSQLTelegram Bot APIVitest

UAES - Ukrainian Community Spain

Built from scratchOwn product

A self-populating community platform that discovers content via AI search, enriches it automatically, and generates its own social media presence from platform data.

Ownership & Delivery

  • •Built the entire platform from scratch, including the public site, user dashboards, and admin operations
  • •Designed automated content pipelines: business discovery, AI-powered event search, social media generation
  • •Developed the core listings architecture for 8 content verticals with unified entity patterns
  • •Built content generation system that turns platform data into Instagram stories and carousels automatically
  • •Set up quality pipelines with Playwright E2E and Sentry monitoring

Client Results

  • ✓200+ listings on day one — platform launched with content, not empty
  • ✓Zero content team: discovery, enrichment, and social media run autonomously
  • ✓Consistent social media presence generated from live platform data

Technologies

Next.js 16React 19TypeScriptPrismaPostgreSQLNextAuth v5next-intlFirebaseVercel BlobGoogle MapsTanStack QueryZustandShadcn/Radix UITailwind CSS v4SentryResendPlaywrightVitestStryker

love💗epil Multi-domain SaaS Ecosystem

Built from scratch

A complete product ecosystem spanning the main website, regional domains, admin panel, analytics, CMS, and transactional tools.

Ownership & Delivery

  • •Defined the architecture and boundaries across five interconnected repositories
  • •Set up multi-domain localization supporting 5 countries, 6 languages, and 4 currencies
  • •Built admin workflows to handle RBAC, payments, translations, and bookings
  • •Integrated full-funnel analytics to track users across domains and tie behavior to lifecycle events
  • •Designed the data architecture using Prisma and PostgreSQL to serve product, operations, and AI

Client Results

  • ✓30K+ monthly active users across 5 European domains
  • ✓96% Mobile Performance Score
  • ✓Single ecosystem strategy connecting acquisition, conversion, operations, and analytics

Technologies

Next.js 16React 19TypeScriptPrismaPostgreSQLStripeNextAuthStrapiResendReact EmailVercelGoogle Maps APIFirebaseMicrosoft ClarityZustandTanStack QueryZodi18nextDeepL

About Me

Product Engineer & AI Architect. I design, build, and ship entire systems — from architecture and AI to frontend and operations.

Denis Klymenko
Experience Snapshot
  • â—†Built and scaled the Loveepil platform across web, admin, analytics, and AI services.
  • â—†Delivered 20+ projects (14 from scratch), handling everything from architecture to production release.
  • â—†Led end-to-end product engineering, including localization, payments, and system reliability.

How I Work

  • →Architecture first: I define clear boundaries, data flows, and contracts before writing code.
  • →Product-minded: I focus on connecting business goals with the technical reality of the platform.
  • →Full ownership: I build, ship, and operate systems, making sure they actually work in production.

Engineering Principles

01
System thinking — I design boundaries, data flows, and contracts before writing code
02
Production-first — Every decision is validated against real traffic, real users, real cost
03
Measurable outcomes — 3x load speed, $0.015/dialog, 96% Lighthouse — I optimize what I can measure
04
Ship & iterate — Working product from week 1, not month 3
05
Full ownership — Architecture to deployment to monitoring — no handoffs, no excuses

Career Timeline

I work in a hybrid model: long-term core roles combined with architecture and product engagements.

Corva

Senior Frontend Engineer

Stack

ReactTypeScriptZustandTanStack QueryHighchartsStyled ComponentsJestReact Testing Library

Responsibilities

Owned performance and architecture of drilling analytics dashboards used by enterprise oil & gas clients. Collaborated closely with QA, designers, and PM. Conducted code reviews and designed a 7-phase refactoring playbook for a complex charting codebase.

Achievements

Cut page load from 5s to 1.5s (3x faster) by eliminating render cascades, fixing chart caching, and lazy-loading heavy modules. Restructured the codebase into a domain-driven architecture — zero regressions, no feature freeze.

love💗epil

Product Engineer & AI ArchitectBuilt from scratch

Stack

Next.js 16React 19TypeScriptPrismaPostgreSQLOpenAI APIVercel AI SDKLangfuseStripeMUIDeepLVercel Drains

Responsibilities

Sole developer of an 8-service production ecosystem across 5 countries. Three AI systems live in prod: a 21-tool AI consultant handling bookings, FAQs, and service guidance across 4 channels, an autonomous content engine generating ~70 articles/week, and embedding-powered semantic search. Plus analytics, admin panel, payments, and transactional emails.

Achievements

Deployed a production AI agent running at $0.015 per dialog with near-zero hallucinations. Achieved a 96% Mobile Performance Score. Built cross-domain analytics with phone-based attribution.

Projects

AI Booking Agent (LoveGPT)

A custom AI agent using fine-tuned GPT-4.1 Mini to orchestrate 21 tools. It handles bookings, answers FAQs, and seamlessly transfers to human operators when needed. Fully observable with Langfuse.

Analytics & Attribution Platform

Custom platform that tracks user journeys across 5 country domains. Built a phone-based attribution system to tie CRM bookings back to Google/Meta ads.

Multi-Service Ecosystem Architecture

Designed and implemented the core SaaS platform: 8 services, 3 AI systems, 15 cron jobs. Booking frontend, localized domains, analytics, RBAC admin panel, and autonomous AI content engine.

Blackbird Lab

Senior Full-Stack Engineer

Stack

TypeScriptReact 19Next.js 15ZustandReduxRedux-SagaRESTGraphQLMUIAnt DesignTailwind CSSPrismaPostgreSQLJestReact Testing LibraryGoogle AnalyticsVercel

Responsibilities

Led frontend modernization across 3 internal products, working with QA, backend engineers, and PM. Moved the stack from legacy setups to a unified Next.js architecture. Conducted PR reviews and improved security by integrating automated vulnerability checks into CI/CD pipelines.

Achievements

Rewrote the authentication layer across 3 products, eliminating critical security vulnerabilities in session handling. Migrated 50K+ lines to TypeScript and Next.js — reduced onboarding time for new engineers and cut regression bugs through strict type safety.

S-PRO

Middle Frontend Developer

Stack

ReactReduxRedux-SagaReact Router v4FormikSCSSAnt DesignFlexbox GridLodashMoment.jsNivo RocksESLint (Airbnb)

Responsibilities

Built 2 greenfield React applications from scratch for US and UK enterprise clients. Owned full frontend delivery — from architecture and component design to testing and production release.

Achievements

Delivered Modo Energy analytics platform with 40+ interactive chart widgets for the UK energy storage market. Built Zymergen data visualization tool handling large biotech datasets with complex filtering and drill-down interactions.

Projects

Modo Energy

Real-time analytics platform for energy storage assets in the UK market. 40+ chart widgets, live data streaming.

Zymergen

Data visualization tool for a US biotechnology company. Complex filtering, multi-view analysis, large dataset rendering.

Skills

Technologies and tools I use to build scalable, high-performance applications.

OpenAI
Vercel AI SDK
Langfuse
LangChain
n8n
Anthropic
OpenTelemetry
pgvector
TypeScript
React 19
Next.js 16
Zustand
React Hook Form
Framer Motion
next-intl
i18next
TanStack Query
Node.js
PostgreSQL
Prisma
Stripe
Resend
NextAuth
Strapi CMS
Zod
Material UI
shadcn/ui
Radix UI
Tailwind CSS
SASS
React Email
Vercel
AWS
Git
Firebase
Telegram Bot API
Vercel Analytics
Google Analytics
Google Search Console
Microsoft Clarity
Google Maps API
Sentry
Vitest
Playwright
Stryker
ESLint