Senior engineering, delivered by subscription.

One developer. Full ownership. Human expertise, AI speed.

From AI agents to SaaS platforms — I build and maintain your product, so you can focus on growing your business.

No credit card required

0h

Onboarding

0+

Projects shipped

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Faster than traditional dev

Denys Zaichenko

Why Me

AI can prototype. But who ships it to production?

Tools like Lovable or Claude Code are great at generating code and drafts. That's where their job ends — and where mine begins.

I'm a senior full-stack developer with 8+ years of experience. I use AI the way a craftsman uses precision tools: to move faster without cutting corners. You get production-grade work, clean architecture, and a developer who's still there six months later.

8+ yrs

Senior engineering

5.0 ★

Upwork rating

CET

EU timezone

Certified

Claude Code user

Testimonials

What clients say

Real feedback from Upwork. 5.0 average across every engagement.

“Excellent developer! High-quality delivery and great communication on two of my personal projects. He is efficient, professional, and easy to work with. Highly recommended!”
High-Quality DeliveryGreat CommunicationEfficient

Full-Stack Dev (Python/Next.js): End-to-End SaaS Platform

Mar 2026 · via Upwork

“Denys is a great specialist, and he always does more than required! Very highly recommended!”
Committed to QualitySolution OrientedClear Communicator

Technical Strategy & Architecture Roadmap for AI-powered MVP

Jan 2026 · via Upwork

Rated 5 stars — no written review

Solution OrientedClear CommunicatorAccountable for Outcomes

Full-Stack Dev (Python/Next.js): Pricing Intelligence Platform

Mar 2026 · via Upwork

See full profile on Upwork

How I'm Different

Senior developer. AI-native workflow. One subscription.

Prototyping

AI tools

✅ Fast drafts

Subscription

✅ Feasibility review first

Building

AI tools

✅ Code scaffolding

Subscription

✅ Clean, production-ready code

Deploying

AI tools

⚠️ Manual handoff

Subscription

✅ I handle deployment

Maintaining

AI tools

❌ Not supported

Subscription

✅ Ongoing, included

Scaling

AI tools

❌ Not supported

Subscription

✅ I own the codebase

“AI is your co-pilot. I'm your engineer.”

I don't fight automation — I'm built on it. You bring the idea, AI drafts the first pass, I ship the production system your business relies on.

vs Per-Project

Why subscription beats per-project work

Reliability

Per-project

❌ Depends on the person. Disappears mid-project.

Subscription

✅ One developer, full accountability, always reachable

Availability

Per-project

❌ Limited hours, timezone issues

Subscription

✅ Async-first, CET timezone, response within 4h

Project Management

Per-project

❌ You handle scope, QA, delivery

Subscription

✅ I manage end-to-end

Pricing

Per-project

❌ Hourly. Balloons with revisions.

Subscription

✅ Flat monthly. Cancel anytime.

Delivery speed

Per-project

❌ Often delayed to bill more hours

Subscription

✅ 2–3 days per task, sprint-based

Quality

Per-project

❌ Varies. No long-term accountability.

Subscription

✅ Senior engineer, 8+ years, 50+ shipped products

Codebase context

Per-project

❌ Starts from zero every gig

Subscription

✅ Knows your codebase deeply

Support

Per-project

❌ Ends when the gig closes

Subscription

✅ Ongoing. I maintain what I build.

Freelancers build gigs. I build products that scale.

What I Build

Everything your product backlog needs

AI Agents & Chatbots

WhatsApp, Telegram, and voice bots. Lead qualification, booking, support — fully automated.

LangChainOpenAIAnthropicTwilio

Full-Stack Web Apps & SaaS

Auth, payments, dashboards, multi-tenant architecture — production-ready from day one.

Next.jsReactNode.jsSupabaseStripe

Automations & Integrations

Connect your tools. Eliminate manual work. Custom pipelines that actually hold up.

WebhooksREST APIsCustom workers

Dashboards & Internal Tools

Admin panels, reporting systems, CRMs, role-based portals.

Next.jsTailwindSupabaseRecharts

Landing Pages

Fast, SEO-optimised, conversion-focused. Delivered in 3–5 days.

Next.jsTailwind CSS95+ PageSpeed

Web Scraping & Data Pipelines

Structured data extraction, lead generation at scale, anti-detection and proxy rotation.

PythonPlaywrightPostgreSQL

Recent Work

Shipped projects

18+ production systems delivered — AI agents, RAG, SaaS platforms, and scraping pipelines.

Live

B2B SaaS — AI Web Scraping & GPT Data Extraction

AI-powered web scraping platform with GPT data extraction from PDFs. Automated data pipelines for B2B clients at scale.

Python · OpenAI GPT-4 · Web Scraping · Next.jsView Project
Live

WhatsApp & Telegram AI Chatbot

Multi-channel AI chatbot for WhatsApp and Telegram. Visual flow builder, AI lead scoring, 95+ languages, CRM integration.

Python · OpenAI GPT-4 · WhatsApp API · Next.jsView Project
Live

Multi-Agent AI Orchestration

Mission-control for multi-agent AI systems. Live topology map, workflow builder, real-time monitoring, message tracing across agent swarms.

LangGraph · CrewAI · Python · FastAPIView Project
Live

Enterprise RAG Document Intelligence

Enterprise RAG platform turning thousands of documents into a searchable knowledge base. Hybrid search, page-level citations, accuracy monitoring.

LlamaIndex · Pinecone · Python · OpenAI APIView Project
Live

AI Voice Agent for Phone Calls

AI voice agent answering calls, qualifying leads, booking appointments 24/7. Real-time transcription, sentiment analysis, 20+ languages.

Vapi · Retell AI · Python · LiveKitView Project

Real-Time SaaS Platform & Admin Suite

Real-time SaaS for a digital marketplace. Custom SQL RPC, Role-Based Access Control, real-time updates, admin panel with analytics.

React · Supabase · TanStack Query · Recharts

Pricing

Subscribe to a senior engineer

Transparent turnaround, priority queue on higher tiers, full ownership of what gets built.

Starter

$1,499/month

For startups testing the model

  • 1 active request at a time
  • Small-to-medium scope (bug fixes, features up to ~2 days of engineering work)
  • 3–5 business day turnaround
  • 24h response on weekdays
  • Async via Slack / Telegram
  • Full code ownership
Start Starter Plan
Most Popular

Builder

$2,999/month

For teams shipping weekly

  • 2 concurrent active requests
  • Any scope — features, refactors, integrations
  • 2–3 business days per standard task
  • 4h priority response on weekdays
  • Slack / Telegram + weekly 30-min sync call
  • Full code ownership
Start Builder Plan

Partner

$5,499/month

For products scaling past MVP

  • 3 concurrent active requests + priority queue
  • Any scope including architecture, infra, CI/CD
  • 1–2 days standard · same-day fix for critical bugs
  • 1h priority response on weekdays
  • Slack / Telegram + monthly strategy & architecture call
  • Full code ownership
Become a Partner
What counts as a request? Any scoped unit of work — from a bug fix to a new feature. Small fixes under 1 hour don't occupy your slot. Larger projects (>2 weeks) get broken into requests during kickoff.

Pause or cancel anytime — no commitments

Risk-free: Not satisfied in the first week? Full refund, no questions asked.

How It Works

How work flows

01

Submit a task

Drop your request via Slack or a shared board: new feature, bug, integration, anything.

02

Scope & align

I clarify requirements, break it into a clear deliverable, and confirm the timeline before touching code.

03

Build

I build with AI-assisted speed and human-grade review. You see progress, not silence.

04

Ship & support

Deployed, documented, and ready. I stay on for follow-up iterations — it's included.

FAQ

Frequently asked questions