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⚡ High-Velocity Developer | 100% Success Rate Need results yesterday? I specialize in rapid, high-quality development powered by 15+ years of expertise and modern AI-assisted workflows. I combine the seasoned intuition of a veteran developer with the speed of today’s best tech. Proven: 100% Job Success Score. Fast: Optimized delivery cycles. Smart: Deep AI integration to 10x productivity and feature set. My technical expertise is extensive, encompassing PHP, Symfony / Laravel Framework, MySQL, and noSQL Databases (MongoDB, Redis). I'm proficient in node.js (socket IO framework, express), and JavaScript (Stencil JS, Ionic, React), and have built APIs using common architectures such as REST and GraphQL. Additionally, I bring to the table experience in managing AWS infrastructure and other servers based on the Linux Operating System specifically for hosting PHP / Symfony projects. My portfolio also includes building HTML mobile apps (Hybrid apps in frameworks like Ionic/Cordova). I’ve worked across a range of industries, including e-commerce, affiliate marketing, real estate, automotive, aviation, courier services, and healthcare. I have very good knowledge of Symfony Components, Doctrine ORM, PSR standards. I have also used across various projects Easy Admin, API Platform, DomPDF, Guzzle, SwiftMailer, Contao CMS and Amazon SP-API libraries. I have experience working with big data solutions - BigQuery, Adverity Datatap, building continuous cost-effective scraping solution and reliable process automations using make com (formerly integromat) Particularly, my most recent projects have been centered around the Symfony framework, granting me continuous and profound expertise in the Symfony / PHP ecosystem. My grasp of software development techniques is solid, including writing clean and secure code, object-oriented development, and designing application architecture with a focus on extensibility and scalability. I have recent experience in building projects that integrate AI features through the OpenAI / Fal APIs. For some significant period of time i was reponsible for building and maintaining shopify websites, including building custom theme, plugins that were enriching logically Shopify and also checkout cusotmisations Beyond just development, I make it a point to grasp a thorough understanding of the entire project from the end user's perspective. My years of experience enable me to provide accurate insights and advice on enhancing your project. What excites me most is problem-solving. I thrive on unraveling complex, challenging issues, and the software industry continually nurtures my knowledge and creativity. I'm also a fan of machine learning, possessing experience in Octave and the R language, along with theoretical knowledge in machine learning techniques. Recently, I have gained experience in building apps utilizing OpenAI APIs, further broadening my skill set. I take pride in being a versatile “one-man army” in Full Stack Development, capable of delivering fast, reliable results. My goal is to handle all your development needs efficiently - so you can stay focused, worry-free. I'm on the lookout for new challenges. If you're interested in working with me, I'd be eager to discuss how I can contribute to your project. Paweł

Hello! I’m Alexander, a full-stack developer with 15+ years of experience in delivering high-quality web and mobile applications. Also I specialize in API development and integrations, building seamless connections across platforms and systems. With over 200 successful projects completed worldwide, I focus on delivering scalable, secure, and business-oriented solutions. My workflow combines strong hands-on engineering expertise with modern AI-assisted development. I understand the technologies I work with in depth, so I can build, review, and improve code manually where it matters. At the same time, I use AI tools with precise technical instructions to speed up routine development tasks, improve code consistency, and help clients get results faster with more efficient budgets. 𝗛𝗘𝗥𝗘'𝗦 𝗪𝗛𝗔𝗧 𝗜 𝗖𝗔𝗡 𝗛𝗘𝗟𝗣 𝗬𝗢𝗨 𝗪𝗜𝗧𝗛: • AI-powered SaaS platforms and internal business tools • Custom CRM, ERP, and workflow automation systems • Client / partner portals, and self-service dashboards • AI assistants, ChatGPT integrations, OCR, and document automation • API development and third-party integrations (REST / OpenAPI / Webhooks) • Subscription platforms, payment flows, invoicing, and billing automation • Fintech, payment processing, and banking API integrations • E-commerce platforms, headless commerce, and marketplace systems • Booking, scheduling, appointment, and resource management platforms • Admin panels, back-office systems, and data management interfaces • Legacy PHP / Laravel / JavaScript system modernization • High-performance Laravel applications with Redis, queues, and Horizon • B2B platforms with roles, permissions, teams, and approval workflows • Data scraping, data processing, reporting, and export automation • Real-time applications: chat, notifications, live status, live data • Mobile-friendly web apps, SPA and Flutter mobile applications 𝗠𝗬 𝗣𝗥𝗘𝗙𝗘𝗥𝗥𝗘𝗗 𝗦𝗧𝗔𝗖𝗞 𝗙𝗢𝗥 𝗠𝗢𝗦𝗧 𝗧𝗬𝗣𝗘𝗦 𝗢𝗙 𝗣𝗥𝗢𝗝𝗘𝗖𝗧𝗦: • AI Boosted Development: OpenCode, ChatGPT Codex, MCPs, plugins • Backend / API: Laravel 13, PHP 8.4, Composer • Frontend: npm, Typescript, Blade + Livewire / Vue.js + Inertia.js + SPA + SSR • Styles: TailwindCSS + PrimeVue, SCSS, CSS3, HTML5, Flexbox • Assets: Vite • Mobile: Dart, Flutter (Android / iOS), Riverpod (state management) • Testing: TDD, Pest 4 (unit / feature), Dusk (browser) • DB: PostgreSQL / MySQL / MariaDB / SQLite • AI API: ChatGPT / DeepSeek • Web-server: Nginx + php-fpm / Laravel Octane + FrankenPHP • SEO Markup: Schema ORG, JSON-LD, Opengraph • Money: Stripe / any bank systems • Cryptocurrency: NOWPayments / BitPay • Background Tasks: Cron / Supervisor / Systemd • Queues: Horizon + Redis / RabbitMQ / Kafka • Cache: Redis • API Docs: Swagger / OpenAPI • SSL: LetsEncrypt • Corporate Domain Mail: ZohoMail / Gmail • Full Text Search: Scout + MeiliSearch / Typesense (simple systems), OpenSearch (complex systems) • Transactional Mail Notifications: Brevo / ZeptoMail • Push Notifications: Firebase / Supabase • Maps: Leaflet / Mapbox / Google / Yandex / OpenStreetMap / Geocoding API • Analytics: Google Analytics / Yandex Metrika • Realtime Broadcasting: Laravel Echo, Laravel Reverb (simple systems), Soketi / OpenSwoole (complex systems) • CDN: Cloudflare, Fastly, Selectel, Akamai • API Development: REST API / gRPC, GraphQL, Swagger / OpenAPI, JSON / XML / SOAP • API Testing: Postman • Debug: Laradumps, Xdebug, Mailpit, Horizon, Telescope • I18n: Multi language support • Admin Panel & Data Management: Filament • Architecture: Entity–Service–Presenter (ESP)!!, DDD, MVC, DI, SOLID, GRASP, DRY, KISS • RBAC: Roles / Permissions • Browser Extensions: TypeScript, SCSS, Vite, Chrome / Brave • Hosting: DigitalOcean, Hetzner, VPS / VDS, Cloud Hosting, DNS Settings • OS: Ubuntu 24 • VCS: Git, GitLab (standalone), GitHub • Graphic Design Tools: Photoshop, Illustrator, Figma, Canva • Automation: Telegram Bots / Zapier • Notification Channels: Telegram API, Firebase, Email, SMS, Web Push API • Performance: Pulse 𝗔𝗗𝗗𝗜𝗧𝗜𝗢𝗡𝗔𝗟 𝗕𝗔𝗖𝗞𝗚𝗥𝗢𝗨𝗡𝗗 𝗔𝗡𝗗 𝗘𝗫𝗣𝗘𝗥𝗜𝗘𝗡𝗖𝗘: • API integration: Google, Yandex, 2GIS, VK, Klaviyo, Zoho, CloseCRM, Podio • Email Services: MailerSend, Mailgun • Backend Development: Yii2, Node.js, Express.js, Axios • Frontend Development: Bootstrap 3-5, JavaScript ES6, jQuery, Pixi.js • Databases: MySQL, SQL, Sphinx, Memcached, MongoDB, Firestore • Data Scrapping: DOM Crawler, regex, XPath, Selenium, Puppeteer, Proxies, CAPTCHA Bypass • SEO: Clean URLs, Canonical Tags, Robots.txt, Auto-Generated Sitemaps, Multilingual Support • Real-time features: Socket IO, AJAX, Firebase, WebRTC, WebSockets • Document automation: PHPOffice, LibreOffice, Tesseract OCR • Security: 2F Auth, Google Authenticator, QR Codes, SMS If you're looking for a dedicated developer who combines technical excellence with business insight, feel free to reach out. Let's discuss how I can contribute to the success of your next project. Best regards, Alexander

Are you looking for a long-term partner rather than just another freelancer? I specialize in custom WordPress development and web design with a focus on in-depth research, problem-solving, and building sustainable systems for my clients. I don’t just deliver tasks – I work as part of your team, helping you understand what's not working, proposing practical solutions, and improving your product over time. Many of my clients stay with me for months or even years because they value my strategic thinking, attention to detail, and reliability. Since 2014 I have been creating websites and plugins using Wordpress, HTML5 / CSS3, JavaScript, PHP, MySQL, jQuery. Here are my skills: • Wordpress • Figma to Wordpress • Woocommerce • WPML / Polylang • Metabox / Visual Composer / WpBackery / Elementor / Gutenberg, etc. • HTML5 • CSS3 • jQuery, AJAX • PHP • MySQL • Bootstrap / Foundation / Popular Paid Themes for Wordpress • API: Google, WordPress REST API I’ve worked with a wide range of hosting environments including GoDaddy, SiteGround, Kinsta, Bluehost, and AWS Lightsail – so I know how to adapt to different infrastructures and solve issues quickly. There are a lot of developers who look for quick, easy money on the upwork, but I'm looking for a long-term cooperation, that's why I'm ready to work for you for the first hour absolutely free, it can be a test task or some small task on your current project Looking forward to working together.

Experienced backend Java developer with over a decade of expertise in developing and maintaining high-quality software solutions. My career includes roles at Accenture, Credit Suisse and GFT Group. Based in Poland, I have also worked in London with Luxoft and Unibet, a leading company in the gambling industry. Top-rated Upwork freelancer, ranked in the top 5% of performers with a 100% Job Success Score. Proficient in Java, Spring Boot, REST APIs, and cloud technologies (AWS). Adept at working with distributed international teams, emphasizing clean code practices and delivering challenging projects. Programming Languages: Java, JavaScript, Scala APIs & Integrations: RESTful APIs, GraphQL, WebSocket, RabbitMQ, JMS, Kafka Cloud & DevOps: AWS (Cloudformation), Docker, CI/CD (Jenkins, GitHub Actions) Frameworks & Tools: Spring Framework, Spring Boot, Hibernate, JPA Version Control: Git, GitLab, Bitbucket Databases: MySQL, PostgreSQL, MongoDB, Redis Testing: JUnit, Mockito, Cucumber, TDD Others: Observability, Keycloak, Angular, Maven, Bash

🚀 Top 1% of Talent in 𝐀𝐈-𝐏𝐨𝐰𝐞𝐫𝐞𝐝 𝐅𝐮𝐥𝐥-𝐒𝐭𝐚𝐜𝐤 𝐃𝐞𝐯𝐞𝐥𝐨𝐩𝐦𝐞𝐧𝐭 & Technology Leadership ⚡ Building 𝐀𝐈-𝐩𝐨𝐰𝐞𝐫𝐞𝐝 𝐩𝐫𝐨𝐝𝐮𝐜𝐭𝐬, enterprise platforms, SaaS solutions, and scalable digital ecosystems 🔧 Using modern AI tools including Cursor, Claude Code, GitHub Copilot, GPT-4/GPT-4o, and Claude Sonnet/Opus 🤖 Experienced in AI agents, LLM integrations, AI automation, and multi-agent development systems 🚀 Accelerating development with 𝐀𝐈-𝐚𝐬𝐬𝐢𝐬𝐭𝐞𝐝 𝐞𝐧𝐠𝐢𝐧𝐞𝐞𝐫𝐢, agentic coding, and automation-driven workflows 💻 𝐖𝐇𝐀𝐓 𝐘𝐎𝐔 𝐀𝐍𝐃 𝐘𝐎𝐔𝐑 𝐓𝐄𝐀𝐌 𝐆𝐄𝐓 Full-Stack Web Development Master's - high-performance web application development utilizing React, Node.js, and PHP to build scalable SaaS, FinTech, and Enterprise software. AI & Automation Systems Innovators - custom LLM applications, RAG pipelines, and intelligent workflow automations seamlessly integrated into your infrastructure. 📊 𝐀𝐂𝐇𝐈𝐄𝐕𝐄𝐌𝐄𝐍𝐓𝐒 𝐈𝐍 𝐍𝐔𝐌𝐁𝐄𝐑𝐒 (𝐁𝐔𝐒𝐈𝐍𝐄𝐒𝐒 & 𝐒𝐘𝐒𝐓𝐄𝐌 𝐈𝐌𝐏𝐀𝐂𝐓) 25+ years, 50,000+ engineering hours, 200+ successful launches delivered as a Senior Full Stack Developer and tech leader across global industries. ◾ Full-Stack Web Development for Enterprise & SaaS Platforms: Engineered and launched custom AI-powered SaaS platforms that scaled to millions of active users with 99.99% operational uptime. Accelerated product development cycles by 40% by deploying optimized React component libraries and agile workflows. Backend Architecture & API Engineering (Node.js & PHP): Reduced server infrastructure costs by 50% by migrating legacy monoliths into scalable microservices using Node.js, NestJS, and PHP. Optimized heavy data-processing pipelines, reducing database latency by 70% via tailored PostgreSQL, MongoDB, and MySQL schemas. ◾ AI App Development & Workflow Automation: Developed and integrated proprietary OpenAI GPT, Claude, and Gemini models into operational CRMs, increasing client workflow efficiency by 180%. Successfully deployed secure, HIPAA-compliant healthcare applications and high-security FinTech platforms with built-in Stripe / PayPal integrations. 🎯 𝐖𝐇𝐄𝐑𝐄 𝐖𝐄 𝐃𝐄𝐋𝐈𝐕𝐄𝐑 (𝐂𝐎𝐑𝐄 𝐄𝐗𝐏𝐄𝐑𝐓𝐈𝐒𝐄) As a Full Stack Developer & Solution Architect: I handle the full cycle of Full-Stack Web Development, defining technical roadmaps, designing scalable web applications, and ensuring bulletproof cyber-security protocols. As a Front-End Development Expert: Crafting pixel-perfect, highly responsive user interfaces using React, Next.js, TypeScript, Vue.js, and Angular to ensure maximum conversion rates and premium UX. As a Back-End Development Authority: Designing ultra-fast APIs and core services with Node.js (Express/NestJS), PHP, Python (FastAPI/Django), and modern Serverless Stack architectures. As a Cloud & DevOps Engineer: Implementing enterprise-grade cloud deployments via AWS, Google Cloud, and Azure, utilizing Docker, Kubernetes, and automated CI/CD pipelines. 🛠 𝐓𝐄𝐂𝐇 𝐒𝐓𝐀𝐂𝐊 & 𝐀𝐑𝐂𝐇𝐈𝐓𝐄𝐂𝐓𝐔𝐑𝐄 𝐄𝐂𝐎𝐒𝐘𝐒𝐓𝐄𝐌 Frontend Suite: React, Next.js, TypeScript, Tailwind CSS, Vue.js, Angular, Responsive Web Design. Backend Core: Node.js, NestJS, Express.js, PHP, Python, FastAPI, Django. Databases & Caching: PostgreSQL, MongoDB, MySQL, Redis. APIs & Global Integrations: REST APIs, GraphQL, Webhooks, Stripe, PayPal, Twilio, SendGrid. Cloud & DevOps Platform: AWS (Amazon Web Services), Google Cloud, Azure, Docker, Kubernetes, Jenkins, GitHub Actions CI/CD. 🧠 𝐃𝐄𝐄𝐏 𝐈𝐍𝐃𝐔𝐒𝐓𝐑𝐘 𝐄𝐗𝐏𝐄𝐑𝐈𝐄𝐍𝐂𝐄 AI & SaaS Startups: Rapid MVP development, RAG pipelines, AI chatbots, and predictive analytics tools. FinTech & E-commerce: High-load payment gateways, customized checkout solutions, compliance, and ledger systems. Healthcare & PropTech: Automated workflow systems, secure patient portals, CRM platforms, and real-time data visualization dashboards. Enterprise Automation: Heavy B2B platforms, marketplaces, and cross-platform integrations. ⚡ 𝐇𝐎𝐖 𝐖𝐄 𝐖𝐎𝐑𝐊 𝐓𝐎𝐆𝐄𝐓𝐇𝐄𝐑 Strategic Discovery: As a CTO, I align your business goals, success metrics, and timeline constraints before writing a single line of code. Architecture Blueprinting: We map out the core database schemas, React frontend components, and Node.js / PHP API flows to ensure long-term scalability. Agile Iteration: Backed by the senior engineering powerhouse at Onix-Systems, we deliver high-velocity sprints with predictable, production-ready releases every 2 weeks. DevOps & Launch: Secure deployment across AWS/GCP/Azure with ongoing tech partnership and proactive optimization based on product metrics. Looking for a Senior Full Stack Developer and a Full-Stack Web Development team to turn your complex concept into a world-class, scalable web platform? 𝐋𝐞𝐭’𝐬 𝐜𝐨𝐧𝐧𝐞𝐜𝐭! Send over your project brief, scope, or existing codebase notes, and I’ll provide a high-level strategic roadmap for your next big launch. ☎️

# You need an honest and dedicated person passionate about technology # You see value of me running a 40x man software house built organically Software engineers from Poland are consistently ranked among the world's best, frequently placing in the TOP 3 globally on platforms. If you're still reading here, it means we might be a fit. I handle full products or build a dedicated team to works for you. I have clients working with for 12+ years now, but also do on-time proof of concept jobs. I like what I do as I enjoy bringing tech value and meeting people. I'm now a serial founder, advisor and a VC investor in Sweden and Singapore funds. But don't just take my word for it: 💬 “Not only was I impressed with the timely delivery of quality products, but I was also impressed by his integrity. I recommend Kacper 100% and would be happy to speak to anyone to provide more details!” – Brad M.
 💬 “Kacper, your company was able to deliver a working product where others have failed.” – Jamie J. 💬 “These guys have turned me around. They were flexible, responsive, fast, gave great feedback and got the job done. They have become my "go to" dev team.” – Tony C.
 💬 “Milo team has been fantastic and as dedicated as our employees in delivering high quality code and software.” – Mojgan H.
 💬 “Milo has delivered all the benefits of outsourcing with none of the problems.” - Mark M. 
 Here's a boring list of what my team and I can do for you. Hopefully Upwork will position my account higher because of this nice list below: ✅ Pre-Implementation Analysis (PIA): Before writing a single line of code, we create a clear roadmap through collaborative workshops to: • Define your business goals and user workflows • Reduce development risks by addressing challenges upfront • Speed up delivery with well-defined technical plans • Stay on budget by avoiding costly surprises What you get: • Business analysis - Goals, workflows, feature alignment • Technical architecture - Tech stack, UI/UX prototypes, scalability strategies • Development roadmap - POC to full product launch milestones • Workshop insights - Actionable next steps ✅ UI/UX Design & Product Design - User-Friendly Interfaces: Our design process creates beautiful, intuitive experiences: • UX research to understand user needs • Rapid prototyping and wireframes • High-fidelity mockups and design systems • Usability testing for seamless experiences 🛠️ Design tools: Figma, Adobe XD, Sketch, InVision, Balsamiq, Axure, Proto, Framer ✅ Full-Stack Development: • Architecture: Client-Server, Layered, Event-Driven, Peer-to-Peer (P2P), Plug-ins, Microservices, MVC ✅ Frontend & Backend Technologies: • Frameworks: Django, React, Angular, Node , Vue, Ember, Semantic-UI, Backbone, jQuery, Qt, Flutter, React Native • Languages: JavaScript, Python, C++, Qt, C, HTML, CSS, Rust, Perl, Go, TypeScript, SQL, Objective-C, Swift, Assembly, R • Databases: PostgreSQL, Redis, Elasticsearch, MySQL, SQLite, Oracle, MongoDB, SQL Server • DevOps: Git, Jenkins, Docker, Kubernetes, AWS, Ansible, Microsoft Azure, Vagrant, CI/CD pipelines, Sentry, Google Cloud, Selenium ✅ Mobile & Web Applications: • Cross-platform mobile apps (iOS, Android) • Progressive web applications (PWA) • Enterprise web solutions • API development and integrations ✅ Testing & QA: Comprehensive testing strategies: • Test-Driven Development - Catch issues early • Manual testing - Real-world scenario validation • Automated testing - Performance and accuracy • Cross-platform testing - Web, mobile, desktop, embedded systems ⚙️ QA Platforms: • Web: Chrome, Safari, Edge, Opera, Firefox, Brave • Mobile: Android, iOS, ChromeOS, Tizen • Desktop: Windows, macOS, Linux, ChromeOS • Embedded: Raspberry Pi, Arduino, SparkFun, Beagleboard, BeagleBone Black, NVIDIA, Rock Pi, SimpleLink, UDOO, QNX, VxWorks, Seeed, Intel Nuc, Embedded Linux, Odroid-C2, Banana Pi, Qualcomm Snapdragon • Protocols: I2C, SPI, USART, USB, DMA, I2S, ADC, DAC, CAN, Ethernet 🛠️QA Tools: TestRail, Selenium, Appium, Cypress , Postman, JMeter, Robot Framework, BrowserStack, Cucumber, Katalon, Squish, Zephyr, Bugzilla, Testim, SoapUI 💼 Industries we serve: • FinTech & Blockchain solutions • Healthcare & Biotech applications • E-commerce & Marketplaces • Education & EdTech platforms • Business Operations software • Embedded Systems & IoT • Travel & Hospitality apps 👨🏻‍🏫 Advisory & Fractional CTO Services: With 15+ years building software across 4 continents I can consult on: • Product strategy and technical roadmapping • Technology selection and architecture decisions • Team scaling and development processes • Investor-ready technical due diligence Ready to take your idea from concept to reality? Let’s talk. 📞