I'm a full-stack web developers with many years of experience working with different teams and technologies. Through the years, I had to wear many hats - from frontend developer to Linux server sysadmin. I help small design agencies to manage their servers, build their websites and keep everything secure. I focus mainly on WordPress websites and PHP web applications. I'm not afraid of working on the legacy code, I still maintain an old platform written in PHP5. So if you want to free up your development team from legacy burden, I'm the person you want to hire. I've been working remotely for more than 6 years, and I know the power of good communication.

# 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. 📞

Your AI prototype works in a notebook. Making it survive production (async queues, retry logic, latency budgets, real users, whatnot), - that's where I come in. Backend: - Production-ready APIs (FastAPI, Django, Flask) - Database design and performance tuning (PostgreSQL, Supabase) - Secure authentication, roles, and permissions - Refactoring unstable or experimental AI-heavy codebase - Dockerized deployments and cloud readiness AI and LLM systems - LLM-powered automation - Custom AI agents and assistants (LangChain) - Optimizing AI pipelines for latency, reliability, and cost - Hardening AI features for production use Automation and AI Workflows - AI-driven workflow orchestration (human-in-the-loop, fallback logic) - End-to-end automation using n8n, Zapier, Make - Connecting AI systems to internal services and third-party APIs My tech stack: Claude Code (yes, I use it a lot to save time and be productive!), Python, FastAPI, Django, Flask, PostgreSQL, Supabase, Docker, Git, LangChain, Kubernetes, GCP, Azure. My recent production projects: • AI Support Ticket Processing System Built an end-to-end backend for an AI system that automates ticket routing and resolution. Focused on latency optimization and building reliable fallback mechanisms so the LLM doesn't hallucinate critical client data. (Tech: FastAPI, LLMs, PostgreSQL) • Back-end developer at a Czech fintech company (Fair Play). Developed and shipped critical features in a high-stakes environment on GCP/Kubernetes. Improved test coverage from 60% to 92%, reduced deployment failures by 80%, and optimized services to handle peak loads with zero downtime. Result: Faster feature releases and enhanced system reliability in a compliance-heavy industry. • Part-time Python back-end developer in a foreign company Glasswall Solutions. Worked on unit tests, bug fixes and project features. We were using Azure as our cloud service provider. Dealt with Paramiko Python library. • Custom CRM development at Hyperbach company This is an internal CRM / HRM platform. It includes 3rd-party API integrations, REST API development, and DB management. It is being written from scratch in Python, Flask, Alembic, PostgreSQL, Docker, Vue.js. Delivered a robust internal tool that automated HR processes, saving the team 20+ hours/week in manual work and scaling to support 500+ users seamlessly. • Custom FastAPI backend for SaaS business I designed and implemented a production-grade FastAPI backend for a mid-size internal SaaS tool used by a distributed team. The project required a clean, scalable architecture capable of supporting multiple user roles, growing feature sets, and third-party integrations. The backend was built using an asynchronous, modular structure, allowing the system to handle high loads and remain maintainable as new features are added over time. If you have an AI prototype that needs to become a real product or you need a solid backend built from scratch, let's talk. 🔥 Last updated: Saturday, 20 July 2026

Over 20 years experience as software engineer and over 8 years as manager and director. Specialize in full stack, cloud and application development, with extensive experience in design, maintenance, and integration work, including DevOps (CI/CD) and related infrastructure, from prototypes to very large scale. Passionate about ensuring business is heading in the right direction, efficiently delivering quality work of my teams, practicing compassionate communication using NVC, and enabling engineers to be the best they can be. Worn many hats prior to management, such as developer, QA, architect, operations and team lead, documenter, and technical project manager.

Specialties: SMS,SMS Gateways,Kannel,Jasmin,Bulk SMS Software,SMS Lead Generation Software, Fortumo, Twilio, Plivo,Clickatell, SMPP 3.4 , HTTP REST API,AT Commands, GSM Modules,telecommunication,VOIP,SIP,IVR. Languages: English(Fluent), French(Fluent), Arabic (Fluent) Programming Skills: PHP 5&7, PL/SQL, shell Scripting, Perl Scripting, Java, Oracle/Mysql,Oracle Forms, Oracle Reports, Solaris/Linux Unix, Application Servers, Web services, advanced XML technologies, SOA patterns.

Data Engineer From 2021 till date - to design, develop, and maintain scalable data pipelines and workflows using Python/Perl, MySQL, Flask API - to integrate data from multiple sources into data warehouses and lakes, ensuring quality and consistency; - to monitor, troubleshoot, and optimize data workflows and ETL processes; - to collaborate with analysts, engineers, and product teams to understand data requirements and implement solutions; - to ensure data security, compliance, and governance standards are met; - to participate in code reviews and maintain high engineering standards; - to stay current with emerging data engineering technologies and recommend improvements to enhance data platform quality and scalability. Website Developer - 2011 to 2017 Perl CGI developer in a UK based company. Data Scraper - 2019 till date working as a part time consistent data scraper using Perl techniques

Experienced Solution Architect with Expertise in AWS, Django, Flask, ReactJS, and Complex App Development 𝐊𝐞𝐲 𝐒𝐭𝐫𝐞𝐧𝐠𝐭𝐡: Building Long-term Partnerships & Delivering High-impact Solutions 𝐒𝐩𝐞𝐜𝐢𝐚𝐥𝐭𝐲: Complex App Development, API Integration & Cloud Architecture With over 𝟐𝟎+ 𝐲𝐞𝐚𝐫𝐬 of experience as a seasoned IT professional and entrepreneur, I specialize in providing cutting-edge web development and cloud-based solutions. I have held roles ranging from application programmer and automation engineer to Scrum Master, technical mentor, and subject matter expert. I bring a wealth of expertise in various domains, including 𝗟𝗼𝗴 𝗠𝗮𝗻𝗮𝗴𝗲𝗺𝗲𝗻𝘁, 𝗩𝘂𝗹𝗻𝗲𝗿𝗮𝗯𝗶𝗹𝗶𝘁𝘆 𝗠𝗮𝗻𝗮𝗴𝗲𝗺𝗲𝗻𝘁, 𝗲𝗖𝗼𝗺𝗺𝗲𝗿𝗰𝗲, 𝗮𝗻𝗱 𝗪𝗲𝗯 𝗦𝗲𝗿𝘃𝗲𝗿 𝗣𝗲𝗿𝗳𝗼𝗿𝗺𝗮𝗻𝗰𝗲 𝗢𝗽𝘁𝗶𝗺𝗶𝘇𝗮𝘁𝗶𝗼𝗻. I have partnered with startups and established enterprises like Loggly, Alert Logic, McAfee, BlackStratus, and Hoffman Patent Firm, among others. In my current role, I focus on creating strategic outsourcing partnerships that help clients accelerate time to market, cut operational costs, and concentrate on their core competencies. 𝗧𝗲𝗰𝗵𝗻𝗶𝗰𝗮𝗹 𝗘𝘅𝗽𝗲𝗿𝘁𝗶𝘀𝗲: ▄ 𝗦𝘆𝘀𝘁𝗲𝗺 𝗗𝗲𝘀𝗶𝗴𝗻 & 𝗦𝗼𝗹𝘂𝘁𝗶𝗼𝗻 𝗔𝗿𝗰𝗵𝗶𝘁𝗲𝗰𝘁𝘂𝗿𝗲: 20+ years of hands-on experience leading complex software development projects. ▄ 𝗖𝗹𝗼𝘂𝗱 𝗖𝗼𝗺𝗽𝘂𝘁𝗶𝗻𝗴 (𝗔𝗪𝗦): Proficient in EC2, SQS, DynamoDB, SNS, RDS, CloudTrail, SES, EBS, Load Balancers, and CI/CD deployment pipelines using Docker, Jenkins, and GitLab. ▄ 𝗕𝗮𝗰𝗸𝗲𝗻𝗱 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁: Expertise in Django, Flask, and Node.js, including the Django Rest Framework. ▄ 𝗦𝗲𝗿𝘃𝗲𝗿𝗹𝗲𝘀𝘀 𝗔𝗿𝗰𝗵𝗶𝘁𝗲𝗰𝘁𝘂𝗿𝗲𝘀: Experience with AWS Lambda, API Gateway, and Node.js. ▄ 𝗗𝗲𝘃𝗢𝗽𝘀 & 𝗔𝘂𝘁𝗼𝗺𝗮𝘁𝗶𝗼𝗻: Skilled in GCP, Kubernetes, Docker Compose, production deployment, and Python/Perl-based automation. ▄ 𝗦𝗜𝗘𝗠 & 𝗦𝗲𝗰𝘂𝗿𝗶𝘁𝘆: Specialized in developing and integrating SIEM products and vulnerability scanners. 𝗧𝗲𝗰𝗵𝗻𝗶𝗰𝗮𝗹 𝗦𝗸𝗶𝗹𝗹𝘀: ► 𝐋𝐚𝐧𝐠𝐮𝐚𝐠𝐞𝐬: Python, C++, C#, Java, Perl ► 𝐅𝐫𝐚𝐦𝐞𝐰𝐨𝐫𝐤𝐬: Django, Flask, Django REST, Magento, ReactJS, VueJS, Zend ► 𝐃𝐚𝐭𝐚𝐛𝐚𝐬𝐞𝐬: MS SQL, MySQL, PostgreSQL, MongoDB, Oracle ► 𝐂𝐈/𝐂𝐃 𝐓𝐨𝐨𝐥𝐬: Docker, Jenkins, GitLab CI, Github Actions, AWS Code Pipeline ► 𝐂𝐥𝐨𝐮𝐝 𝐏𝐥𝐚𝐭𝐟𝐨𝐫𝐦𝐬: AWS (EC2, S3, RDS, CloudFront, CloudTrail), GCP ► 𝐕𝐞𝐫𝐬𝐢𝐨𝐧 𝐂𝐨𝐧𝐭𝐫𝐨𝐥 & 𝐏𝐫𝐨𝐣𝐞𝐜𝐭 𝐌𝐚𝐧𝐚𝐠𝐞𝐦𝐞𝐧𝐭: Git, Jira, Confluence, VersionOne, MS Project, XMind ► 𝐓𝐞𝐬𝐭𝐢𝐧𝐠 & 𝐀𝐮𝐭𝐨𝐦𝐚𝐭𝐢𝐨𝐧: NUnit, Selenium, Cypress

WhatsApp Official API Developer - Meta Tech Provider With 7+ years of experience in full-stack development and messaging API integration, I specialize in building scalable, secure, and high-performing communication platforms using Meta (WhatsApp) Cloud API, Twilio, 360Dialog, and custom messaging gateways. Whether you want to automate customer conversations, integrate real-time chat in your product, or build an AI-powered communication assistant, I help you move from idea → architecture → production with confidence. 🔹 CORE SERVICES & PLATFORM EXPERTISE 📘 FACEBOOK / INSTAGRAM (META) ✔️ Facebook & Instagram App Creation ✔️ Facebook Marketing API & Instagram Ads API ✔️ Facebook Custom Audience Sync ✔️ Instagram Graph API Development ✔️ Meta Business Verification & App Reviews ✔️ Facebook Lead Ads API Integration ✔️ Messenger & Instagram Direct Chatbots ✔️ Facebook Ads API with Custom Backends ✔️ Facebook / Instagram Comments API ✔️ Facebook / Instagram Content Posting Integration ✔️ Instagram Marketplace Development ✔️ Facebook pages API integration ✔️ Meta Marketing AI Agent / Agentic AI Marketing 📱 WHATSAPP BUSINESS API ✔️ WhatsApp Cloud API CRM Integration ✔️ WhatsApp On-Premise API Setup ✔️ Webhook Configuration & Templates ✔️ Embedded Signup Flow ✔️ QR Code-Based WhatsApp Automation ✔️ Multi-Tenant CRM Integration ✔️ WhatsApp chatbot flow builder ✔️ WhatsApp Broadcast API integration ✔️ WhatsApp account reinstatement ✔️ WhatsApp marketing lite API integration ✔️ WhatsApp MM Lite Event Tracking Integration 🎵 TIKTOK DEVELOPER API ✔️ TikTok App Setup & Business Verification ✔️ TikTok Ads API Integration ✔️ TikTok Webhook CRM Integration ✔️ TikTok Direct Post API Management API integration ✔️ TikTok Developer App Audit Support ✔️ TikTok Creator Marketplace (TTCM) API integration 👻 SNAPCHAT API ✔️ Snapchat Developer App Integration ✔️ Snapchat Ads API ✔️ Lead Sync via Snapchat Webhooks ✔️ Business Verification 👔 LINKEDIN MARKETING API ✔️ LinkedIn Ads API ✔️ CRM Integration via LinkedIn Webhooks ✔️ Developer App Setup ✔️ Business Page & Profile Verification 📺 YOUTUBE DATA API ✔️ YouTube Channel & Video Analytics ✔️ YouTube Data API Automation ✔️ Comment Reporting & Moderation ✔️ Dashboard ⚙️ Tech Stack Languages & Frameworks: Java (Spring Boot), Python (Django, FastAPI), PHP (Laravel), React, Next.js Messaging APIs: Meta / WhatsApp Cloud API, Twilio, 360Dialog, Vonage, Firebase, Slack, MS Teams Cloud & Infra: AWS Lambda, Docker, Kubernetes, Redis, Celery, Jenkins, CI/CD Databases: PostgreSQL, MySQL, MongoDB, Elasticsearch AI & Automation: OpenAI, LangChain, RAG Pipelines, Voice AI, Chatbots, Agentic AI 💬 Client Promise 💡 Clear communication | no hidden costs ⚡ Fast delivery | without cutting corners 🧩 Full ownership | you get all code & documentation 💰 100% refund if expectations are missed Let’s build something that actually communicates. Message me to discuss your project. Regards, Barshan Hassan ⚡ Skill Tags Full Stack Developer | JAVA | Python | PHP | WhatsApp Business API | Meta API | Communication | MERN Stack | Elementor Pro | WooCommerce | React Developer | Custom APIs | E-commerce Development | Web Design | SEO Optimization | Payment Gateway Integration | Responsive Design | MongoDB | Node.js | Express.js | React.js | MySQL | Shopify | Website Redesign | Website Maintenance | Figma to Code | Custom APIs | HTML5 | CSS3 | JavaScript | Technical SEO | API Integrations | Frontend Development | Backend Development | Website Security | Speed Optimization | REST API | Web Applications | Database Optimization | Bug Fixing | Website Migration Custom WordPress Themes | Elementor Landing Pages | WooCommerce Customization | React Frontend Developer | Node.js Backend Developer | MongoDB Aggregation | Website UI/UX Improvement | Speed Optimization Expert | Technical SEO Expert | Third-Party API Integration | RESTful API Developer | Website Performance Optimization | Responsive Web Development | Mobile-First Web Design | JavaScript ES6+ | E-commerce Payment Integration | Shopify Customization | Shopify to WordPress Migration | Next.js | Website Debugging | Bug Fix Specialist

I'm Hong Kong based Senior Full Stack Engineer, 18+ years of experience, Top Rated Plus, 100% job success across all Upwork jobs. Before working as a freelancer I used to work for various multi-national corporations (BNP Paribas, Citibank, UniCredit, Astek, Prenetics, EPAM). I'm an AI Native engineer and deliver high-quality code in hours, not weeks. Proficient across the top AI coding tools - Claude Code, Cursor, Codex, OpenClaw, Hermes. I'm a fast learner. When a feature exposes a knowledge gap, I close it quickly with Google Gemini Notebook and my own AI learning app, StudyForge AI, then apply what I learned back into the code. I've solo-built StudyForge, an open-source agentic AI study platform on Supabase (live in production). Stack: Next.js 16 + Fastify on Postgres RLS, with LangGraph agents, pgvector RAG, agent memory, LiteLLM routing, and SSE streaming. On several recent Upwork jobs I led delivery as Technical Lead on 3-4 person product teams: backlog refinement, sprint planning, stories and estimation, architecture decisions, code review, and unblocking juniors - while staying hands-on and shipping features across the stack.

Hi! I've only been on upwork for a couple years now, but come with a ton of experience from solving complex technical issues for over 20 years. With a strong engineering background on top of a solid understanding of which processes, tools, and strategic approaches need to be applied to each new project, I'm able to hit the ground running and provide measurable results backed up by data. The skillsets I've acquired are relevant to the needs of modern digital marketing, from programming website backends to designing ecommerce flow for maximum purchase conversion, to visual design and search engine optimization. I also know when to bring in an outside expert, and provide quality control on the work that they provide so as to maintain maximum success in all cases. My skillsets include: - CSS, PHP, HTML - Search Engine Optimization / SEO - Search Engine Marketing / SEM (AdWords and other pay-per-click marketing) - Linux shell programming (bash, csh, sh) - SSH, IPtables, Putty, Key-based authentication - Perl programming - Ecommerce portal configuration & troubleshooting (woocommerce, shopify, volusion, resmark, checkfront) - Web hosting & configurations with cPanel, WHM - VPS server provisioning, configuration, & API programming - AWS, Linode, Digital Ocean, Azure, Google Cloud Platform, Binary Lane, Oracle Cloud, IBM Cloud - System administration & security updates & maintenance for WordPress sites - Linux system administration - Web UI/UX evaluation ... And lots more. If it's something I haven't listed, please ask and I'll give an honest answer so you can be confident in what I can provide.