Hi, I’m Zlata. I’m basically a typical American software developer... just living in Ukraine now. And I always work in the EST timezone. I’ll write everything in any tech stack you have 😄 I’m a Software Engineer with 8+ years of experience as a Ruby on Rails developer, React developer, Node.js developer, Python developer, and .NET developer. I work with Ruby on Rails, React, Node.js, Python, .NET, PostgreSQL, Docker, AWS, JavaScript, TypeScript, API development, API integration, and SaaS software development. I help companies build and improve SaaS platforms, ERP systems, CRM tools, dashboards, marketplaces, internal systems, API products, and complex web applications using Ruby on Rails, React, Node.js, Python, and .NET. My focus is clean product logic, stable delivery, scalable architecture, and software that stays easy to maintain as the business grows. 📊 My Achievements in Numbers: 🔶 Ruby on Rails Developer for a Construction Application Platform ▪ Helped build a Ruby on Rails + React platform for managing construction applications, reviews, documents, and stakeholder workflows. ▪ Reduced application review time by 42%. ▪ Supported 18,500+ construction applications processed in the first year. ▪ Helped the product reach $1.4M ARR within 14 months. ▪ Worked with Ruby on Rails, React, PostgreSQL, Docker, AWS, S3, and API integration. 🔶 React Developer for a Construction Materials ERP SaaS ▪ Helped improve a complex ERP SaaS platform for concrete, aggregates, and asphalt producers. ▪ Improved sales, pricing, and operational workflows through better product logic and scalable software architecture. ▪ 98% of demo users became clients after product improvements. ▪ 91% of users rated the interface as clear and intuitive. ▪ The product later raised $3.4M. ▪ Focused on React, Ruby on Rails, SaaS workflows, API development, and complex web application structure. 🔶 Node.js Developer for an Aviation Maintenance SaaS ▪ Helped improve a complex aviation maintenance SaaS product used by field teams. ▪ 96% of demo users became clients after the product improvements. ▪ 97% of field users adopted the product after the first try. ▪ Reduced user errors by 41% and made onboarding 62% faster. ▪ Supported product logic, API integration, dashboards, and connected SaaS workflows using Node.js, React, Ruby on Rails, and API development. 🔶 Python Developer for an AI Healthcare SaaS ▪ Supported an AI-powered healthcare platform that grew from a chatbot into multiple AI agents for clinics and hospitals. ▪ The product raised $20M+. ▪ Helped support workflows that increased patient visits by 31%. ▪ Helped reduce call abandonment by 98%. ▪ Worked with Python, API integration, automation workflows, AI-related product logic, and scalable SaaS architecture. 🔶 .NET Developer for a Utility Billing Platform ▪ Helped improve utility billing workflows for a SaaS platform processing complex customer, billing, and reporting data. ▪ Helped process $14M+ in utility bills within 6 months. ▪ Reduced billing cycle time from 9 days to 1.5 days. ▪ Supported 96% client retention through better product stability and workflow clarity. ▪ Worked with .NET, React, API development, reporting logic, SaaS architecture, and reliable software delivery. Why should you hire me as a Software Engineer? ▪ 8+ years of experience with Ruby on Rails, React, Node.js, Python, .NET, JavaScript, TypeScript, PostgreSQL, API development, API integration, and SaaS software development. ▪ 120+ successful projects delivered across B2B SaaS, ERP, CRM, healthcare, construction, logistics, fintech, aviation, and internal business platforms. ▪ Strong experience with Ruby on Rails, React, Node.js, Python, and .NET for SaaS products, dashboards, admin panels, API-first platforms, integrations, automation, AI features, and enterprise systems. ▪ I use Claude, Cursor, GitHub Copilot, and ChatGPT to speed up research, debugging, refactoring, and delivery. ▪ I work well with founders, CTOs, product managers, and teams that need clear communication across Ruby on Rails, React, Node.js, Python, and .NET products. What I can help you with: ✔️ Build or improve Ruby on Rails SaaS products ✔️ Create React dashboards, portals, admin panels, and SaaS interfaces ✔️ Build Node.js services and API integrations ✔️ Support Python automation, data workflows, and product logic ✔️ Work with .NET systems and connected software platforms ✔️ Build API-first products with Ruby on Rails, React, Node.js, Python, .NET, PostgreSQL, Docker, and AWS ✔️ Improve performance, stability, and maintainability of existing Ruby on Rails, React, Node.js, Python, and .NET applications ✔️ Support SaaS, ERP, CRM, fintech, healthcare, logistics, construction, and internal tools Need help with Ruby on Rails, React, Node.js, Python, .NET, API development, or SaaS development? Message me and let’s discuss your product. 📩🤝

I'm a Manual QA Engineer with 4 years of experience and 5,500+ hours of hands-on testing across web, mobile, and API products. I've worked with SaaS platforms, CRM systems, logistics solutions, and e-commerce websites - helping teams ship stable releases by catching issues before real users do. I work best on long-term contracts where the team needs a reliable QA engineer who can own the full testing cycle independently - from test plan to release sign-off, without constant handholding. WHAT I DO ✓ Manual QA Testing ⦁ Functional, regression, smoke & exploratory testing ⦁ End-to-end flow validation ⦁ UI/UX testing & design verification against Figma ✓ Web & SaaS Testing ⦁ User auth & registration flows ⦁ Dashboard & admin panel validation ⦁ Role & permission testing ⦁ Cross-browser & cross-device coverage ✓ Mobile App Testing ⦁ iOS & Android testing on real devices ⦁ Cross-device & responsive design validation ✓ API Testing ⦁ Endpoint validation via Postman ⦁ Request/response verification ⦁ Integration & error handling checks ✓ E-commerce Testing ⦁ Checkout & payment flows ⦁ Product catalog & filtering ⦁ Order management & post-purchase flows WHAT I'VE SHIPPED SaaS CRM Platform Full-cycle QA for a cloud-based CRM system. Tested user flows, dashboards, role & permission logic, and third-party integrations. Validated API contracts via Postman, ran structured regression before each release, and maintained test cases in TestRail. Logistics Platform End-to-end QA for a logistics web platform. Covered order management, driver assignment, status tracking, and API sync validation. Ran full regression cycles before releases and reported bugs in Jira with clear reproduction steps and severity classification. E-commerce & Corporate Websites Tested multiple web products including e-commerce stores and corporate websites. Covered checkout flows, UI consistency, cross-browser compatibility, and functional testing across different devices and screen sizes. TOOLS I USE DAILY Jira · TestRail · Zephyr · Postman · Figma · Chrome DevTools · SQL · Git / GitHub WHY CLIENTS WORK WITH ME ✓ Sharp eye for detail - I catch what others miss ✓ Clear, developer-friendly bug reports ✓ Fast turnaround without cutting corners ✓ Honest feedback, not just a checklist ✓ Product-oriented mindset Let's find the issues before your users do. Manual QA Engineer, Software Tester, QA Analyst, Quality Assurance, Manual Testing, Web Testing, Mobile Testing, iOS Testing, Android Testing, Functional Testing, Regression Testing, Smoke Testing, Exploratory Testing, UI/UX Testing, API Testing, Postman, Cross Browser Testing, Bug Reporting, Test Case Design, TestRail, Jira, Figma, SaaS Testing, E-commerce Testing, Logistics Platform Testing

🚀 The Top 3% of Talent in iOS & 𝐀𝐈-𝐏𝐨𝐰𝐞𝐫𝐞𝐝 Mobile Development ⚡ 𝐀𝐈-𝐀𝐬𝐬𝐢𝐬𝐭𝐞𝐝 Development Workflows Accelerating Delivery by 30–40% ⚡ Experience Building 𝐀𝐈-𝐏𝐨𝐰𝐞𝐫𝐞𝐝 Mobile Apps, SaaS Platforms & Enterprise Solutions 🤖 Leveraging Modern 𝐀𝐈 𝐓𝐨𝐨𝐥𝐬 Including Cursor, Claude Code, GitHub Copilot, GPT-4/GPT-4o & Claude Sonnet 👉 WHAT YOU GET ✔️ Senior iOS Developer & AI App Developer - 10+ years experience, intelligent high-performance builds, extreme client impact, end-to-end ownership. ✔️ Swift iOS Developer - native modern interfaces, 18–27% user engagement lift, custom ChatGPT integration, and ultimate trust. ✔️ iOS Mobile App Developer - 30–40% faster release cycles, cleaner AI/UX workflows, stronger user retention across Mobile SaaS platforms. 👉 ACHIEVEMENTS ✔️ 10+ years, 17,000+ hours, dozens of products delivered as a native iOS developer, swift developer, and senior full stack developer ai and mobile application developer workflows. ✔️ Massive client impact and direct revenue generated through full-cycle development as a top-performing iOS developer ai specialist and Apple app developer. ✔️ 100,000+ active users on a popular festival companion app where native iOS mobile app development execution lifted repeat engagement by 27%. ✔️ 10,000+ users in Healthcare App and medical-compliant systems where iOS application development cut data friction by 40% using an intuitive doctor directory website layout. ✔️ High-converting generative AI pipelines, 34% faster action handling in E-commerce Marketplace App, smart assistants, and Fintech App deployments as an experienced iOS developer. ✔️ 90% faster mobile processing and local LLM execution, 80% lower client-side crash workload, 65% fewer server-roundtrips through clean API Integration, push notifications, and iOS developer ai features. ✔️ 5–8 weeks shorter Startup MVP to Pilot Launch, 35% fewer bugs through refactor existing codebase tasks, smart automation, and clean App Store submission pipelines. 👉 WHERE I DELIVER ✔️ As an iOS developer ai specialist - engineering smart features, OpenAI API configurations, Claude API integration, voice AI, and generative AI features into native mobile application development. ✔️ As a SwiftUI developer - dynamic systems with pixel-perfect design, smart assistants, local storage, and complex UI layout across iOS mobile app development and Mobile SaaS infrastructures. ✔️ As an experienced iOS developer - native applications and AI-powered mobile application frameworks built from scratch, delivering 30–40% faster iteration cycles. ✔️ As a native iOS developer - clean MVVM, MVC, and Clean Architecture implementation with secure backend API integrations from Early-Stage Prototype to live product launch. ✔️ As an iPhone app developer - complex core features including OAuth, Apple Sign-In, image & vision processing, audio transcription, in-app purchase setups, and multi-tier subscription systems with RevenueCat. ✔️ As a mobile software engineer - handling advanced audio/video solutions, geolocation services, location tracking, Apple Maps, and real-time chat messaging using WebRTC. ✔️ As a long-term iOS developer - driving ongoing maintenance, smart feature enhancement, bug fixing, and performance tuning as a reliable long-term collaboration partner. 👉 INDUSTRY IMPACT ✔️ AI Mobile App & Smart Assistants - ChatGPT integration, custom AI chatbot agents, voice AI features, generative AI prompts, LLM tools, and automated smart recommendations. ✔️ Fintech App & Wallet Systems - secure mobile banking apps, online payment setups with Stripe and PayPal, and robust local data storage solutions. ✔️ Healthcare App & Telemedicine - secure health tracking platforms, medical records access, and real-time data sync for complex health environments. ✔️ Marketplace App & Booking Systems - scalable service marketplaces, real-time booking, automated push notifications via APNs, and interactive user reviews. ✔️ Fitness App & Workout Platforms - custom sports systems, automated coaching apps, and full-cycle development for high-end Golf Training & Coaching Platforms. 👉 HOW I BUILD ✔️ 10+ years as a mobile app developer: engineering applications with Swift, SwiftUI, UIKit, Xcode, OpenAI API, Claude API, and Objective-C for legacy codebase migration and system scaling. ✔️ Architectural patterns and clean execution: utilizing MVVM, MVC, Clean Architecture, and VIPER alongside Core Data, Realm, and Firebase Cloud Messaging. ✔️ End-to-end product deployment: driving the entire cycle from Proof of Concept, prototype development, QA & DevOps integration, up to a successful publish to App Store workflow. Looking for an elite Senior iOS Developer, Swift Developer, or a trusted ai mobile app developer who can build an iPhone application from scratch, build an AI-powered iOS application, or handle full-cycle end-to-end development? Let's connect! Send an invite and let’s talk about your project goals. ☎️

Hello! 👋 I am a full-stack developer with more than five years of experience in web and mobile development, now also focused on AI-powered software development, Claude Code workflows, RAG systems, and practical AI automation for real business tasks. My core background is still strong engineering with .NET, Blazor, .NET MAUI, C#, Web API, Azure, DevOps, SQL databases, MongoDB, DigitalOcean, NGINX, IIS, and modern web technologies. On top of that, I help clients integrate AI into existing products, build internal AI tools, design AI workflows, and use tools like Claude Code to speed up development, improve code quality, and automate complex technical tasks. 🔧 Key Skills: - AI Development & AI Workflow Design - Claude Code setup, usage, and project workflows - RAG systems / Retrieval-Augmented Generation - LLM integration into web and business applications - AI assistants, internal copilots, and knowledge-base chatbots - Vector search, embeddings, document processing, and semantic search - Prompt engineering and AI workflow automation - .NET Core and .NET Framework - Blazor - .NET MAUI - Web API - SignalR - Mapbox - Android SDK - OpenGL - Azure Cloud - Azure DevOps CI/CD Pipelines - DigitalOcean - NGINX, IIS - SQL & Database Management: MS SQL Server, PostgreSQL, SQLite, MongoDB, Azure Storage - Entity Framework, Dapper - Web Technologies: HTML, CSS, JavaScript, TypeScript 🚀 Professional Experience: - Successfully designed and implemented numerous web, mobile, and backend applications, leveraging the power of the .NET ecosystem to deliver efficient and reliable solutions. - Built and designed AI-powered workflows, including RAG-based systems, document search, knowledge-base assistants, and automation tools for real business processes. - Experienced in working with Claude Code and AI coding workflows to analyze existing codebases, plan features, improve productivity, and support faster software delivery. - Skilled in integrating LLMs into applications, connecting AI models with databases, APIs, documents, and internal business data. - Managed and mentored development teams, fostering a collaborative and innovative work environment. - Skilled in overseeing all phases of the software development lifecycle, from initial requirements gathering to deployment and maintenance. - Proficient in various .NET technologies, with a strong understanding of front-end, back-end, cloud, and mobile development. - Skilled at identifying and resolving complex technical issues, optimizing performance, and ensuring application stability. 🤝 Let's Connect! Let’s connect and explore how I can help you build reliable software, improve your existing product, or bring AI-powered features into your business workflow. 🌟

Senior Full-Stack Developer • Performance Optimization Expert Java, Kotlin, JavaScript (frontend/backend), C++, Python, PHP, Perl SQL/NoSQL, Web/Desktop apps, Automation, Web Scraping I help companies make their software faster, lighter, and more efficient. 20+ years of hands-on experience in system performance tuning, profiling, solving bottlenecks, and refactoring legacy systems. If your application is slow, unstable, memory-hungry, or needs deep analysis — I can fix it. ⸻ 🧩 My Core Expertise • Performance optimization (Java/JVM, databases, backend services) • Query optimization, memory leak detection, code profiling • Refactoring legacy code, stabilizing old systems • Full-stack development (Java/Kotlin + JS, Python, PHP, Perl, C++) • Web automation & scraping • Systems analysis, debugging, complex issue resolution ⸻ 🚀 What I Deliver • Faster request processing • Reduced memory & CPU usage • Significantly improved database performance • Clean, maintainable, well-structured code ⸻ 🤝 Availability Open to long-term or part-time collaboration (30–40 h/week). Also interested in innovative startups: your idea — my implementation. ⸻ Let’s make your software fast, stable, and scalable!

Hey there! Thanks for dropping by my profile 🙌 My name is Daria and welcome to my profile! With 5 years under my belt as a Full-stack developer, I have demonstrated my talent for building reliable and high-performance web applications. My skills are centered around ReactJS, which covers core front-end development tools such as TypeScript, JavaScript, React.js, React Native, HTML5/CSS3, Next.JS framework, Redux | MobX, and a set of other frameworks and libraries for building UI and UX. Technical skills I possess: ⚡️ JavaScript ⚡️ TypeScript ⚡️ React.JS react-query react-bootstrap react-pdf react-storybook ⚡️ Next.JS ⚡️ React Native ⚡️ Redux.JS ⚡️ MaterialUI ⚡️ TailwindCSS ⚡️ styled-components ⚡️ SCSS / module CSS / Less / Sass ⚡️ HTML5 / CSS3 ⚡️ WebRtc ⚡️ Auth0 ⚡️ Bootstrap Additional Skills: - Figma / Zeplin / Sketch - GitHub / GitLab / Bitbucket - Jira / Asana / Trello / Slack / Discord 🚀 Apart from technical skills, I have excellent problem-solving and communication skills. I am comfortable working in a team environment. Thanks to my English I can easily communicate with teammates via voice meetings besides usual messages in Slack. And I don't mind working with team meetings where video is required. With a passion for learning and staying up-to-date with the latest web development trends, I am committed to delivering high-quality, user-centric web applications that meet business requirements and exceed expectations. ❓ What will you get if will hire me? 1️⃣ Good front-end engineer with a passion for coding. My skills and expertise in Front-End development (React/Next/JavaScript/TypeScript/MUI/TailwindCSS/styled-components/react-storybook) 2️⃣ Clear and transparent partner with great communication skills. I am always open to communicating with my teammates and stakeholders to achieve the best results. 3️⃣ Client-oriented approach. I am always doing my best to meet deadlines and deliver clean and structured code. Could you kindly drop me a message to initiate a conversation? See you!

Senior .NET ASP.NET C# Full-stack developer with 8 years of experience. Since the start of my career, I’ve delivered 80+ projects across logistics, transportation, warehousing, inventory, automotive, supply chain and marketplace domains. I work with founders, product teams, and enterprises, helping companies cut development costs by up to 50% while delivering stable, production-ready software. 👨‍💻 My skills include: • Working with .NET frameworks from the very first contact: .NET, .NET Core, Node.js, NestJS, ASP.NET, ASP.NET Core, ASP.NET MVC, C#, Entity Framework, API • Full-stack development: .NET C#, ASP.NET , React, Next.js, Angular, HTML, CSS, TypeScript, Tailwind, Javascript • For databases I usually use MySQL, SQL Server, PostgreSQL, Redis, MongoDB • Cloud and deployment(DevOps) experience in : AWS, Azure, Microsoft Azure, CI/CD pipelines, Docker, Kubernetes, CI/CD. • Real time notifications and messaging: SignalR, WebSocket • Architecture & Scalability: Monolithic Architecture, Microservices, Event-Driven Systems • Security & Authentication on JWT, OAuth 2.0, Role-Based Access Control • Integrations: Payment Gateways, CRM/ERP Systems, Third-Party APIs, GPS & Tracking Services 🔍 Key Project Highlights: Transportation Management System Using .NET Framework, ASP.NET, ASP.NET MVC, React, SQL Server, Web API, SignalR, JWT, Azure developed a transportation management system supporting shipment lifecycle management, dispatch planning, vehicle allocation, driver assignments, route optimization, administrative and operational dashboards and real-time shipment tracking. Maintained Travelport Universal API integrations using C# / .NET Inventory Platform/ERP Spent years as a Lead .NET full stack developer building a comprehensive inventory ERP system for supply chain management. Real-time inventory tracking, automated order intake, stock replenishment, and delivery coordination modules with microservice integrations, Web APIs, and cloud-based infrastructure. Tech stack I used: .NET, ASP.NET Core, C#, React, Next.js, TypeScript, SQL Server, Entity Framework, and RESTful APIs. Marketplace for Car Auctions (Automotive marketplace) Built from scratch multi-tenant automotive SaaS with integration with Rapid Car Check API and Anthropic Claude AI API (calculates the purchase offer based on car details and condition) . I used a .NET-based backend with microservice architecture and SQL database integration. Key features: dealer management, vehicle listings, bidding workflows, subscriptions, payment processing, and vehicle verification services developed with ASP.NET Core, React+ Next.js, Entity Framework, RabbitMQ, and SQL Server and TypeScript. Custom tracking and monitoring App IOS/Android As a Team Lead contributed to a real-time tracking platform for monitoring field operations, assets, and vehicle movements with live GPS tracking, geolocation, task management, photo uploads, and operational reporting. Built scalable APIs, integrated Google Maps and GPS providers, implemented push notifications and offline synchronization. Tech: ASP.NET Core, Web API, React, React Native, TypeScript, SignalR, SQL Server, Azure, Google Maps API. CRM Reviewed the architecture of a multi-role CRM for a printing business. Using .NET Core, improved the system performance by 30% through database query tuning and backend refactoring. Using .NET Core, ASP.NET Core, C# developed new modules for order processing and invoicing. Key things to consider: 📎 8+ years as a web and app developer and .NET software engineer 📎 110+ clients worldwide (US, UK, EU, Middle East, Australia) 📎 50% cost reduction through AI-assisted coding (Claude Code, Codex, Cursor and Chat GPT) and proven frameworks 📎 Delivered 70+ Web platforms, SaaS products, and Mobile apps 📎 Strong focus on architecture, clarity, and long-term maintainability If you’re looking for a full-stack .NET developer, a reliable .NET engineer or someone who can grow into a long-term technical partner – I’m ready to help, click the green INVITE button, and let’s give it a try.

Expert React Js Developer | Next.Js Developer 📈 5000+ hours of work only on Upwork! ⭐5-Star ratings across all projects 💼 9+ years of experience 🚀 30+ completed projects and 0 negative feedback ⚡ Job success score 100% 💎 Top Rated Plus Freelancer (Top 2% on Upwork) 🙋 I’ve worked as a FrontEnd React Engineer, Frontend Lead, and Senior Software Engineer for prominent companies like ExpoPlatform, DeepChecks, Haystack, Vuukle, and Found.ee. I am a (Top 2% on Upwork) with 9+ years of experience building cutting-edge software solutions for my clients. I focus on creating scalable, robust, and efficient applications using various modern technologies and frameworks. I have experience working with various web projects, including SaaS, web apps, and website development. 🏆 𝗪𝗛𝗬 𝗖𝗛𝗢𝗢𝗦𝗘 𝗠𝗘? 🔹 I’ve worked with clients across various industries, from e-commerce to healthcare, delivering websites that not only look great but also drive conversions and growth. 🔹 Over 9 years of hands-on experience in web development and exceptional feedback from satisfied clients worldwide. 🔹 Experience with Enterprise Clients like ExpoPlatform, DeepChecks, Haystack, Vuukle, Found.ee, and more. 🔹 5000+ working hours on Upwork with proven results. 🔹 Flexible Availability: 50+ hours/week, across time zones. 🔹 Certified JavaScript Developer. 🔹 Certified React Developer. 🔹 Certified React Native Developer. 🔹 Available almost 24/7 to meet your needs and bring your ideas to life. 🔹 Long-Term Contract Focus on Upwork. I'm available for a call to discuss your project needs and ensure we align on your goals. Contact me today to start our journey toward a successful partnership and effective development 🔥 𝗖𝗢𝗥𝗘 𝗦𝗞𝗜𝗟𝗟𝗦 & 𝗘𝗫𝗣𝗘𝗥𝗧𝗜𝗦𝗘 ✅ Core skills: JavaScript (ES6+), HTML, HTML5, and CSS3. ✅ Front-end frameworks/libraries: Java, JavaScript, React.js, React js, Next.js, NextJs, Next js. Familiar with ReactJS, NextJS, React Query, react-hooks, and React Router, leveraging TypeScript for enhanced type safety. ✅ Experience with CSS preprocessors (Sass, LESS), styled-components, and frameworks like Tailwind CSS, Bootstrap, Ant Design, Material-UI, and Radix UI. ✅ Responsive Web design(RWD) and cross-browser compatibility. ✅ Version control tools: Git, GitHub, GitLab, Bitbucket. ✅ Webpack, Gulp, NPM, Yarn. ✅ State management libraries: Redux, Redux-Saga, MobX, or React Context. ✅ RESTful services and APIs, 3rd part APIs integration for fetching data. ✅ Performance optimization and UX/UI best practices. ✅ Jest, React Testing Library, Playwright, or Cypress. ✅ Storybook. ✅ Firebase (Realtime / Database / Cloud / Hosting). I have limited experience with Node.js, WordPress, Flutter, Java, Vue, Shopify, Python, and Angular, but I am always open to learning new technologies when needed. I have worked on full-stack projects where the backend was built using Firebase, handling authentication, database management, and cloud functions. Additionally, I have basic experience in design, allowing me to collaborate effectively with designers and contribute to UI/UX improvements. 🌟 𝗪𝗛𝗔𝗧 𝗗𝗢 𝗜 𝗣𝗥𝗢𝗩𝗜𝗗𝗘? 📗 Clear Communication: I prioritize effective communication and keep you updated every step of the way. 📗 Problem Solving: I’m detail-oriented and always deliver clean, optimized code to ensure your site runs smoothly. 📗 On-Time Delivery: Meeting deadlines is important to me, and I pride myself on delivering projects on schedule, every time. 📗 Custom Web Applications: CRM systems, project management tools, healthcare platforms, and data-driven dashboards. 📗 SEO & Performance Optimization: I focus on optimizing your website for fast loading speeds, SEO best practices, and mobile compatibility. 📗 Analysis of your requirements and providing tasks' estimation 📗 Writing clear, well-structured code in a timely manner 📗 Build stunning UIs with ReactJS or NextJS. Specialize in SPAs, PWA (Progressive Web Apps), and responsive designs tailored for any device. 📗 I develop tailored solutions for unique business needs, whether it’s building e-commerce platforms, integrating booking systems, or adding custom forms. 💬 𝗟𝗘𝗧’𝗦 𝗖𝗢𝗡𝗡𝗘𝗖𝗧! Feel free to reach out if you're ready to take your project to the next level. I’m excited to collaborate and build something exceptional together! 📞 Available for a call to discuss your project goals and create a clear roadmap. Thanks, Oles Telikhovskyi

🚀 Engineering Scalable Web Ecosystems from Concept to Production. I am a Senior Full Stack Engineer and Technical Lead with deep expertise in building complex, high-load systems. My approach focuses on creating flexible architectures that allow businesses to scale rapidly without accumulating technical debt. I manage the full development lifecycle: from designing robust databases and complex backend solutions in Node.js (NestJS) and Python (FastAPI) to crafting high-performance user interfaces with Next.js and React. 💡 Full Stack Expertise & Strategic Solutions: - Backend Architecture: Designing complex APIs and microservices using Node.js (NestJS) and Python (FastAPI) for AI workloads. I specialize in asynchronous data processing, message queues (RabbitMQ/Redis), and heavy query optimization. At Stepler — Sweden's #1 fitness app, 10M+ users — delivered high-load backend architecture with MongoDB optimization reviewed and validated by the core MongoDB team. - Modern Frontend (Next.js/React): Building fast, SEO-optimized web applications using SSR (Server-Side Rendering) and SSG. High focus on Web Vitals and seamless UX. - Browser Extensions (Plasmo): Unique expertise in developing sophisticated Chrome Extensions (Manifest V3) that function as standalone products or integrated ecosystem tools. - Database & Logic Design: Advanced knowledge of PostgreSQL, MongoDB, and Redis. I design data architectures capable of handling millions of records while maintaining peak performance. 💼 Featured Full Stack Impact: Enterprise SaaS Platforms: Developed modular ERP/CRM systems with custom business logic and complex role-based access control (RBAC). AI-Powered Tools: Integrated Large Language Models (OpenAI/Claude) into web interfaces, browser extensions, and Python AI microservices to automate user workflows. Real-time Dashboards: Created secure platforms for real-time data analytics using WebSockets and GraphQL for instantaneous updates. ⚙️ Technical Stack: Languages: TypeScript/JavaScript, Python. Backend: Node.js (NestJS, Express), Python (FastAPI · AI microservices). Frontend: React, Next.js, Redux Toolkit, Zustand, Tailwind CSS. Browser Extensions: Plasmo Framework, Chrome API (Manifest V3). Databases: PostgreSQL, Redis, MongoDB, Supabase. APIs: GraphQL (Apollo), REST, WebSockets.

If it can break, I will find it before your users do. I am a QA Engineer with 8+ years of hands-on experience in manual and automation testing, covering web, mobile, and API layers. I have worked on production-grade products in fintech, e-commerce, SaaS, telecom, healthcare, and edtech, including platforms like SimilarWeb, NAGA/CAPEX, Finalto, Tag Heuer, and BP. Whether you need structured manual coverage, a scalable automation framework built from scratch, or both, I adapt to your product and your stage. 🔍 What I test: • Web and mobile applications (iOS & Android) • REST APIs (Postman, Swagger) • Fintech and payment flows, including balances, transactions, and auth • E-commerce and marketplace platforms • SaaS products and back-office systems • Browser extensions and progressive web apps 🤖 Automation expertise: I build and scale automation frameworks from scratch using Playwright, Selenium, Selenide, and Cypress, integrated into CI/CD pipelines via GitHub Actions and GitLab CI. I have maintained 98%+ regression pass rates on high-risk transactional products and reduced regression execution time by up to 85% through parallelization and pipeline optimization. 🛠 QA Tools & Platforms: → Manual Testing: Functional, Regression, Exploratory, Smoke, Sanity, UAT, Cross-Browser & Cross-Device → Automation Testing: Selenium, Cypress, Playwright → Bug Tracking & Management: JIRA, Trello, Asana, Linear, ScribeHow → Collaboration & Reporting: Google Sheets, Notion, Slack → Testing Platforms: BrowserStack, physical devices → Performance & Analytics Tools: GTmetrix, SimilarWeb → Documentation: Test Plans, Test Cases, Checklists, FRS, User Manuals → Stack: Selenide · TypeScript · Java · Python · TestRail · Confluence · GitHub Actions · GitLab CI · Docker · Allure · Chrome DevTools 📋 What I deliver: • Test plans, test cases, and checklists built around your business risks • Clear bug reports with repro steps, screenshots, and video proof • Automation frameworks with CI/CD integration and reporting • API and regression test suites ready for continuous delivery • Release readiness assessments and go/no-go recommendations 🏭 Industries I have covered: 🏥 Healthcare · 🛒 E-Commerce & Marketplace · 💳 Fintech · 💻 SoftDev · 🎯 Marketing · 📚 E-Learning · 💼 Business Solutions · Telecom · EdTech · Green Energy ⭐ Why work with me: → Deep expertise in both manual and automation QA across web and mobile → Sharp eye for edge cases and critical defects that others tend to miss → Structured test documentation that makes testing repeatable and transparent → Comfortable in Agile and Waterfall environments, no ramp-up time wasted → Flexible hours to fit your timezone and project rhythm → Website crawling and SEO functionality checks included where needed ✅ Agile & Waterfall | Manual & Automation | Available across any time zone I treat quality as a shared responsibility, not a final checkpoint. I embed into your workflow, understand your risk areas, and focus coverage where it matters most. If you are looking for a QA engineer who is reliable, technically strong, and easy to work with, let's talk. Manual Testing API Testing Web Testing Mobile App Testing Regression Testing Cross-Browser Testing Test Case Design Jira UI/UX Testing End-to-End Testing Functional Testing Bug Reports Quality Assurance Payment Gateway Testing iOS Testing Android Testing Test Plan Usability Testing User Testing Software Testing Manual QA AI Testing Chatbot Testing Voice AI Testing NLP Testing Mobile App QA Conversational AI AI Model Evaluation Reverse Testing PWA Testing Progressive Web App Validation Progressive Web Application AI Apps Testing AI Apps OpenAI ChatGPT Sora Gemini Generative AI Chatbot Manual QA Engineer QA Engineer Manual Engineer Software Tester Software QA Engineer SQA Engineer Bug Hunter Automation QA Engineer Mobile App Tester Website Tester Quality Assurance Engineer Part Time QA Engineer Software QA Specialist Test Automation Engineer Automation and Manual QA Web App Engineer Software Quality Assurance Engineer QA Automation Engineer UI/UX Auditor & QA Engineer App QA Engineer Manual Testing Specialist SaaS Product Tester End-to-End Manual Engineer Web/App Tester Detail-Oriented Manual Tester Front End QA Tester QA Bug Bounty Tester Website Functionality Tester Website QA Engineer