Hi! I'm Oleksii, a seasoned Full-Stack Developer specializing in scalable web applications, mobile solutions, and API integrations. With 10+ years of experience and a proven track record on Upwork (Top Rated Plus, 100% success score), I help businesses transform ideas into powerful digital solutions. TECHNICAL EXPERTISE: Backend: Python (Django, FastAPI, Flask), PostgreSQL, Redis, Celery Frontend: Vue.js, JavaScript, HTML5, CSS3, Bootstrap Mobile: Cross-platform development (Cordova), iOS/Android deployment Cloud & DevOps: AWS (EC2, S3), Linux, API integrations Specialized: AI/Chatbots, IoT integration, E-commerce, Booking systems WHAT I DELIVER: - Complete web applications from concept to production - Cross-platform mobile apps (iOS/Android from single codebase) - API development and third-party integrations - E-commerce and booking platforms - AI chatbot solutions and automation - Database optimization and system architecture PROVEN RESULTS: • 50+ successful projects completed • 3000+ hours worked for long-term clients • 100% job success score on Upwork • Apps successfully deployed to App Store/Google Play • Platforms serving thousands of active users RECENT PROJECT HIGHLIGHTS: • AI-powered chatbot platform with multi-engine integration • Cross-platform IoT application with hardware communication • Digital library system with OCR and full-text search • Multi-city booking aggregator with commission tracking • E-commerce platform for children's activities WHY CHOOSE ME: ✓ Fast turnaround without compromising quality ✓ Clean, maintainable, and well-documented code ✓ Excellent communication and regular updates ✓ Full project lifecycle management ✓ Post-launch support and maintenance Ready to bring your vision to life? Let's discuss how I can help you achieve your goals with a solution that's built to scale and perform. Available for both short-term projects and long-term partnerships.

I’m a Python developer specializing in web scraping, automation, and data extraction. Over the past few years, I’ve worked on real-world projects involving high-performance scraping, API integrations, and custom automation tools. I focus on building reliable, efficient solutions that can handle large datasets and run without constant supervision. 🔹 What I do best: Web Scraping & Automation: - Scraping structured and dynamic websites (requests, BeautifulSoup, Playwright) - Async scraping using asyncio / aiohttp for high performance - Handling pagination, rate limits, and large-scale data extraction - Extracting clean, structured data (CSV, JSON, databases) Data Processing & Integration: - Working with APIs (Twitch, Telegram, Instagram) - Data parsing, transformation, and validation - Experience with SQLite and basic knowledge of PostgreSQL Desktop & UI Applications: - Desktop apps using PySide6 (Qt) - Lightweight UI solutions with Flet and CustomTkinter - Building user-friendly interfaces for automation tools Bots & Automation Tools: - Telegram bots (aiogram, telethon) - Workflow automation and notification systems 🔹 Relevant experience: - Built high-performance scrapers handling large datasets (thousands of items per run) - Developed a complex real estate scraper with regional data aggregation and filtering - Created automation tools for Twitch chat processing, scoring systems, and giveaways - Worked on a startup project involving scraping, PostgreSQL, Docker, and server-side workflows - Experience deploying and testing scripts in Linux environments 🔹 Additional Projects: - Built a cross-platform habit tracking app (HTML/CSS/JS + Tauri) with calendar tracking and progress visualization 🔹 My approach: - Prefer fast and lightweight solutions (async requests) whenever possible - Use browser automation (Playwright) only when necessary - Focus on stability, data accuracy, and maintainable code Let’s build something efficient and reliable.

Talented and dependable developer • Parsing and scraping websites. • Prestashop, Symfony, PHP. • Django and Python. • Instagram and Telgram bots. • Developing and maintaining the front end functionality of websites with usability. • Designing prototypes for apps and websites. • Creating logos, banners and buttons for websites. • Writing cross-browser compliant XHTML, CSS & JavaScript. • Developing websites that have a consistent feel and look throughout all web properties. • Providing technical support to end users. • Identifying and correcting software deficiencies. • Devising SEO strategies based around specific keywords. • HTML coding. • template development and installation on CMS.

Audit | Google Tag Manager | Google Analytics 4 | Server-side tagging | Data Analytics | Data Visualization Welcome to my profile. I’m a software engineer who understands analytics from the inside. I don’t just configure GA4, GTM, and pixels. Where a typical tracking specialist only works through the interface, I can go deeper: build custom GTM templates, implement server-side tracking, connect APIs, design ETL pipelines, set up data warehouses, and fix the real causes of data loss, duplication, and tracking errors. I deliver analytics end-to-end: from audit and architecture to implementation, debugging, data storage, processing, and reporting. You get not a set of disconnected configurations, but a reliable analytics system that actually helps your business make decisions. I’ve been working in software development since 2007. Senior level in Golang, PHP, Python, and C++. Former team lead. For the last 4 years, I’ve been focused on marketing data, web analytics, server-side tracking, ETL, and data infrastructure. 🛠️ I Can Help With 📈 GA4, GTM, DataLayer setup and debugging 📈 Meta Pixel + Conversion API 📈 TikTok Pixel + Events API 📈 Pinterest Pixel + Conversion API 📈 Google Ads tracking: web + server-side 📈 LinkedIn Insight Tag 📈 Microsoft Ads tracking 📈 GDPR / cookie consent setup 📈 Enhanced Ecommerce and conversion tracking 📈 Event tracking: forms, scrolls, clicks, videos, custom events 📈 Custom GTM templates 📈 Server-side tracking architecture 📈 API integrations 📈 ETL, mapping, validation and data processing 📈 BigQuery, PostgreSQL, ClickHouse, Snowflake 📈 Dashboards and reporting 🔍 Audit First: Not sure what is broken in your tracking or what should be improved first? Start with an audit. I can review your current analytics setup and provide a clear report with: ✅ how your tracking system works today ✅ where data is being lost, duplicated, or misattributed ✅ what should be fixed first ✅ what can be improved or added ✅ what architecture will work better for your business 🤝 What You Get: You are not locked into implementation with me after the audit. You can use the report to compare approaches, validate other opinions, and make the right decision for your business. Many clients continue working with me long-term because they need more than setup - they need a technical analytics partner. Send me a message, and I’ll tell you what kind of audit makes sense for your setup.

Python Developer | Data Scraping & API Integration. Stop wasting time on manual data entry. I specialize in building robust web scrapers and data extraction pipelines using Python (Playwright, Pandas, BeautifulSoup). Whether you need to pull thousands of records from marketplaces, automate repetitive data tasks, or connect custom APIs, I deliver clean, fast, and scalable solutions. Let's get your data working for you.

What is manual work costing you? I build AI automation systems that help businesses generate qualified leads, reactivate CRM contacts, and convert more opportunities into customers through better follow-up and automation. Top Rated on Upwork with 100% Job Success, I’ve built 100+ automation workflows and helped businesses eliminate 1,000+ hours of manual work across outreach, CRM, follow-up, and internal operations. With 7+ years of experience in AI, ML, and automation, I create practical systems for customer acquisition, reactivation, and conversion using n8n, Zapier, Make, APIs, and custom AI integrations. 🔹 Core Expertise ▪️ AI Agents for Lead Generation & Outreach ▪️ Cold Email Outreach Systems ▪️ CRM Automation & Customer Reactivation ▪️ Follow-Up & Conversion Automation ▪️ Lead Qualification, Enrichment & Routing ▪️ Sales Automation & Revenue Workflows ▪️ Workflow Automation with n8n, Zapier, Make, and OpenClaw ▪️ API Integrations & Custom AI Systems 🔹 What I Build in Practice ✦ Customer Acquisition Systems AI systems that turn outreach into pipeline. Your team spends less time chasing lists, writing one-off messages, and manually keeping follow-up alive. The workflow researches prospects, pulls useful context, prepares personalized messaging, and keeps outreach moving so more qualified conversations make it into your pipeline. ✦ Cold Email Outreach Systems Cold email systems that save time and stop leads from getting lost. Your team no longer has to manage every step manually or rely on memory to keep outbound moving. The workflow handles lead sourcing, enrichment, personalization, sequencing, and CRM updates so follow-up stays organized and more opportunities reach the right next step. ✦ Customer Reactivation Workflows Reactivation workflows that bring old opportunities back to life. Instead of letting past leads and inactive contacts sit untouched in the CRM, your team gets another chance to turn existing data into revenue. The workflow segments past contacts, triggers the right re-engagement sequence, and surfaces the people most likely to respond so valuable opportunities do not stay buried. ✦ Follow-Up & Conversion Automation Follow-up systems that keep interest from going cold. Your team responds faster, misses fewer next steps, and has more chances to turn interest into revenue. The workflow triggers reminders, next-step actions, and timely follow-ups when someone shows interest, replies late, books a call, or goes quiet. ✦ Lead Qualification & CRM Workflows Workflows that keep your pipeline clean and your team focused. Instead of sorting leads by hand and cleaning CRM data manually, your team sees what matters most and what should happen next. The workflow scores, tags, updates, and assigns leads automatically so the right opportunities go to the right place without the usual admin burden. ✦ AI Agents for Business Workflows AI agents that take repetitive work off your team’s plate. Your team spends less time on coordination, admin tasks, and routine back-and-forth, and more time on work that actually needs human attention. The agent can read incoming requests, extract key information, generate responses, update records, and trigger actions across your tools and systems. Typical tools: OpenAI, RAG workflows, n8n, Zapier, APIs, internal tools, CRMs ✦ CRM & Workflow Integrations Integrations that keep your process connected and moving. Instead of dealing with disconnected tools, manual copying, and delayed follow-up, your team gets a smoother process with fewer dropped opportunities. The integration keeps CRM, forms, email tools, spreadsheets, and internal systems in sync so leads and tasks move cleanly from one step to the next. Typical tools: Airtable, Google Sheets, CRMs, forms, email tools, APIs, automation platforms 🔹 Tools & Stack ▪️ Automation Platforms: n8n, Zapier, Make, OpenClaw ▪️ Languages: Python, JavaScript, PHP, SQL ▪️ AI / LLMs: OpenAI, ChatGPT-based systems, NLP, RAG workflows ▪️ CRM / Outreach / Growth Tools: HubSpot, Mailchimp, Airtable, Apollo, EXA, Google Sheets ▪️ Data & Integrations: APIs, webhooks, internal databases, Excel ▪️ Automation Types: lead generation automation, CRM automation, cold email outreach automation, follow-up automation, workflow automation, email automation 🔹 My Approach 1. Find the bottlenecks I look at where leads are being lost, follow-up is slowing down, or CRM processes are creating unnecessary manual work. 2. Build the right workflow I design a system around your actual process so lead handling, outreach, follow-up, and handoffs happen more smoothly and with less manual effort. 3. Improve and scale Once the system is live, I refine it for reliability, speed, and long-term performance so it keeps delivering value as your business grows.

You bring the idea. I bring the working product — Next.js + Supabase, shipped, in production, with real users. No "almost done for 3 months." Here's the thing: most Upwork devs can build a frontend OR a backend well. I do both. I run my own SaaS in production (Built&Written — AI book writing platform), so I don't just write code — I think about shipping, maintenance, edge cases, the things that break at 2am. That's why clients keep coming back: 100% Job Success, 15 completed projects, 5-star reviews across the board. WHAT I BUILD 🚀 SaaS products and MVPs Full applications on Next.js + Supabase. Multi-tenant architecture, RLS-based data isolation, admin panels, user management. From "I have an idea" to "users are paying" in 4-8 weeks. 🛒 E-commerce and online stores Catalog, cart, checkout, orders, customer accounts. Stripe with subscriptions and webhooks done right (not the broken tutorial version). Real-time inventory sync, shipping APIs, admin dashboards. 📊 Dashboards and internal tools For businesses that outgrew Google Sheets but don't want enterprise bloat. Analytics, CRMs, workflow automation, reporting. Built around how your team actually works. 🔌 Integrations and APIs Stripe, PayPal, payment gateways, shipping providers, third-party services, webhook architecture. The boring-but-critical plumbing that makes products actually run. WHY CLIENTS WORK WITH ME I'm not a freelancer who codes when there's time. I'm a co-founder who ships products for a living — and takes on freelance work because I genuinely like solving other people's problems too. Concretely: ✅ I own the full stack. You don't coordinate between 3 contractors. ✅ I make decisions, not just take orders. If your spec has a problem, I'll tell you before it costs you 2 weeks of rework. ✅ Weekly updates with actual progress, not "working on it." You'll always know where the project stands. ✅ Production-grade code from day one. TypeScript strict, proper error handling, no copy-pasted AI mess that breaks in 2 months. ✅ I push back when needed. You're paying for my judgment, not just for typing speed. BACKGROUND → 4+ years building full-stack products → Co-founder of Built&Written — production SaaS for AI book writing and Amazon KDP publishing → Built TechCortex — e-commerce platform with real-time inventory sync across 3 distributors, 500+ SKUs → Worked on enterprise ERP modules, healthcare sites, CRM systems, Figma-to-code conversions, and a number of smaller fixed-scope jobs → 100% Job Success on Upwork, 15 completed projects TECH STACK My home stack (what I do every day): - Next.js 15+ (App Router, Server Actions, RSC) - TypeScript (strict mode, always) - Supabase (Postgres, Auth, Storage, RLS, Edge Functions) - Tailwind CSS + Shadcn/ui - Stripe (subscriptions, webhooks, Connect) Also fluent in: React Query, Zustand, React Hook Form, Zod, PostgreSQL, Node.js, REST API design, Vercel, Docker, GitHub Actions, Sanity/Strapi CMS PROJECTS THAT FIT BEST 📌 MVPs that need to launch in 4-8 weeks 📌 Existing Next.js apps that need a senior pair of hands 📌 Stripe / payments integration done properly 📌 Migrations from old stacks to Next.js + Supabase 📌 Internal tools for teams that outgrew spreadsheets 📌 Long-term partnerships (I do my best work past month 2) If you're tired of devs who disappear, ship broken Stripe integrations, or need to be micromanaged through every task — let's talk. Send a message with what you're building. I'll tell you honestly if I'm the right fit, what it'll take, and how long. No sales pitch, just a straight answer.

🚨 Is your product slowing down as users grow - because the backend nodejs can’t keep up, APIs get messy, and releases become risky? I’m a Senior backend developer with 15+ years in production and 120+ delivered web applications across SaaS, eCommerce, FinTech, logistics, and enterprise software. As a hands-on software engineer and experienced javascript developer, I build scalable systems that move from MVP to stable platforms serving thousands of users. 🏆 Proven Success - 100% client satisfaction on Upwork. ⚡ Performance-First - I design backend nodejs systems that remain fast under load. 🕒 Reliable Collaboration - Clear workflow with qa, product owners, and stakeholders. What I Build ✔ SaaS platforms - multi-tenant dashboards, subscriptions, billing ✔ eCommerce systems - checkout, integrations, analytics ✔ FinTech tools - including a stock trading app and day trading dashboards ✔ Enterprise automation platforms handling 10k+ operations daily 🧩 Backend Architecture & APIs As a senior backend developer, I specialize in clean backend nodejs architecture built on modern node.js standards. I contribute as a node.js developer, leading service design and API structure across production systems. For teams that need dedicated implementation support, I also step in as a reliable node js developer focused on stable and scalable delivery. ✔ API design in the role of api integrator working as backend developer node ✔ Production services delivered in the capacity of node.js backend developer ✔ Additional service-layer ownership provided as nodejs backend developer ✔ Stable deployments managed by an experienced backend engineer ✔ Optimization at the node runtime level when performance bottlenecks appear I’ve rebuilt legacy services, stabilized unstable releases, and redesigned monoliths into scalable backend nodejs environments. Whether joining a project as a backend developer or contributing as a senior node.js developer, I focus on maintainable code and measurable performance gains. 🧠 NestJS & Structured Systems Working as a nestjs developer, I implement scalable modules using nestjs backend patterns. ✔ Authentication, RBAC, billing logic, background jobs ✔ Queue systems and async processing ✔ Migration and refactoring of legacy stacks 🎨 Full Product Delivery While my core role is backend developer, I also operate as a full stack developer and web developer, when projects require ownership across layers. ✔ UI implementation as a react developer using react and react js ✔ Clean front end architecture delivered as front end developer react ✔ Scalable builds using node.js react.js with structured react node flows ✔ Rapid MVP delivery via node.js express.js react.js next.js javascript typescript mvp ✔ Mobile support with react native 📊 Data & Automation ✔ Cross-service automation combining python nodejs ✔ Tooling and scripts delivered as a python developer ✔ Reporting pipelines implemented as data engineer ✔ AI integrations referencing cnn models when required 🤝 Cross-Stack Collaboration I integrate easily into mixed environments. ✔ Collaboration with java developer teams using java spring ✔ Hybrid architectures in java node.js ecosystems ✔ Maintenance and integrations for ruby on rails platforms ✔ UI layers built on laravel vue ✔ Full-stack environments aligned with mern standards I measure product health using clear metrics - from 1k to 50k concurrent users, uptime stability, and release safety. Why Work With Me? 🔹 Senior backend developer mindset - architecture first, code second 🔹 Reliable node.js developer who takes ownership 🔹 Clear documentation and smooth collaboration 🔹 Business-focused delivery - performance, scalability, ROI If you need a senior backend developer who can stabilize backend nodejs, contribute as a hands-on node.js developer, and ship reliable React solutions - let’s discuss your project. 🚀

I’m software developer specializing in full-stack application design and game development. My focus at the moment is full-stack development using Typescript (React, Express, Socket. IO). I’ve built a few small games using Unity and C# from the ground up. In addition, I’ve developed a variety of Python applications: Telegram bots, REST APIs, and administrative websites with Django. I have a hands-on experience in developing using Typescript and Javascript, particularly in creating browser extensions, including automating complex actions as well as API requests in administrative sites. I am also developing my own pet projects in Typescript with React and Next.js. Recently, I’ve started using Go for smaller projects like Telegram bots for it's speed and possibility to easily set it up on my own Raspberry Pi server. I am a fast learner, quickly adapt to new libraries, frameworks, and languages as required by each project. I also possess a working knowledge of Java, C++, HTML/CSS (including TailwindCSS), and PHP, which allows me to contribute effectively across different aspects of a project.

I am a 𝗗𝗮𝘁𝗮 𝗦𝗰𝗶𝗲𝗻𝘁𝗶𝘀𝘁 & 𝗠𝗮𝗰𝗵𝗶𝗻𝗲 𝗟𝗲𝗮𝗿𝗻𝗶𝗻𝗴 𝗘𝗻𝗴𝗶𝗻𝗲𝗲𝗿 with 𝟱+ 𝘆𝗲𝗮𝗿𝘀 𝗼𝗳 𝗰𝗼𝗺𝗺𝗲𝗿𝗰𝗶𝗮𝗹 𝗲𝘅𝗽𝗲𝗿𝗶𝗲𝗻𝗰𝗲 in ML development and 𝟭𝟬+ 𝘆𝗲𝗮𝗿𝘀 𝗶𝗻 𝗯𝘂𝘀𝗶𝗻𝗲𝘀𝘀 𝗱𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁, combining strong analytical expertise with a deep understanding of product strategy and real business goals. I build end-to-end data and ML solutions — from data ingestion and feature engineering to model development, deployment, evaluation, and integration into production systems. My work focuses on delivering 𝗽𝗿𝗮𝗰𝘁𝗶𝗰𝗮𝗹, 𝗺𝗲𝗮𝘀𝘂𝗿𝗮𝗯𝗹𝗲, 𝗮𝗻𝗱 𝘀𝗰𝗮𝗹𝗮𝗯𝗹𝗲 𝗿𝗲𝘀𝘂𝗹𝘁𝘀 while ensuring a smooth collaboration with your team and alignment with your business objectives. 𝗠𝘆 𝗽𝗿𝗶𝗼𝗿𝗶𝘁𝗶𝗲𝘀 𝗶𝗻 𝗲𝘃𝗲𝗿𝘆 𝗽𝗿𝗼𝗷𝗲𝗰𝘁: 𝗗𝗲𝗹𝗶𝘃𝗲𝗿 𝗿𝗼𝗯𝘂𝘀𝘁, 𝗽𝗿𝗼𝗱𝘂𝗰𝘁𝗶𝗼𝗻-𝗿𝗲𝗮𝗱𝘆 𝘀𝗼𝗹𝘂𝘁𝗶𝗼𝗻𝘀 I focus on building systems that are reliable, maintainable, and ready for real-world use — not just prototypes. 𝗘𝗻𝘀𝘂𝗿𝗲 𝗮 𝗰𝗹𝗲𝗮𝗿, 𝘁𝗿𝗮𝗻𝘀𝗽𝗮𝗿𝗲𝗻𝘁, 𝗮𝗻𝗱 𝗰𝗼𝗹𝗹𝗮𝗯𝗼𝗿𝗮𝘁𝗶𝘃𝗲 𝘄𝗼𝗿𝗸𝗳𝗹𝗼𝘄 Keep communication open, align expectations early, and maintain predictable, organised delivery. 𝗨𝗻𝗱𝗲𝗿𝘀𝘁𝗮𝗻𝗱 𝗮𝗻𝗱 𝗮𝗱𝘃𝗮𝗻𝗰𝗲 𝗿𝗲𝗮𝗹 𝗯𝘂𝘀𝗶𝗻𝗲𝘀𝘀 𝗴𝗼𝗮𝗹𝘀 Technical decisions are guided by measurable impact, user needs, and long-term value for the product. 𝗖𝗼𝗺𝗺𝘂𝗻𝗶𝗰𝗮𝘁𝗲 𝗽𝗿𝗼𝗮𝗰𝘁𝗶𝘃𝗲𝗹𝘆 𝗮𝗻𝗱 𝗺𝗲𝗲𝘁 𝗰𝗼𝗺𝗺𝗶𝘁𝗺𝗲𝗻𝘁𝘀 I surface risks early, provide regular updates, and honour deadlines through structured planning. 𝗚𝗿𝗼𝘄 𝘁𝗵𝗲 𝗽𝗿𝗼𝗱𝘂𝗰𝘁 — 𝗮𝗻𝗱 𝘁𝗵𝗲 𝘁𝗲𝗮𝗺 — 𝘁𝗵𝗿𝗼𝘂𝗴𝗵 𝗾𝘂𝗮𝗹𝗶𝘁𝘆 𝗮𝗻𝗱 𝗰𝗹𝗮𝗿𝗶𝘁𝘆 Help shape scalable architecture, improve processes, and support a culture of thoughtful, data-driven decision making. 𝗠𝗲𝘀𝘀𝗮𝗴𝗲 𝗺𝗲 𝗮𝗻𝘆𝘁𝗶𝗺𝗲 - 𝗜’𝗺 𝗼𝗽𝗲𝗻 𝘁𝗼 𝗱𝗶𝘀𝗰𝘂𝘀𝘀𝗶𝗻𝗴 𝘆𝗼𝘂𝗿 𝗽𝗿𝗼𝗷𝗲𝗰𝘁 𝗮𝗻𝗱 𝗿𝗲𝗮𝗱𝘆 𝘁𝗼 𝗵𝗲𝗹𝗽 𝘆𝗼𝘂 𝗺𝗼𝘃𝗲 𝗶𝘁 𝗳𝗼𝗿𝘄𝗮𝗿𝗱!