I build production-grade full stack applications in React and Django — the kind that scale, stay maintainable, and don't fall apart after launch. My current work involves a large-scale geospatial analytics platform where I've built interactive Mapbox maps, AI-powered features, analytics dashboards, and REST APIs — all the way from database design to React UI. If you need a developer who can own the full stack and deliver without handholding, that's where I operate. I'm particularly strong at: building dashboards and data visualization tools, integrating AI/OpenAI APIs, geospatial and map-based apps, and REST API design with Django + PostgreSQL. I care about clean code, honest timelines, and communication that doesn't waste your time. I'll tell you if something isn't feasible — and I'll tell you early.

Senior Software Engineer with 7+ years of experience in full-stack and cloud-native development. Strong expertise in Ruby on Rails and FastAPI, with frontend experience in React.js and Next.js. Skilled in DevOps practices including AWS deployments, Docker, and advanced debugging to ensure scalability and high availability. Experienced in building GIS platforms with PostGIS and Tegola. Committed to delivering scalable, reliable, and production-ready applications across diverse domains. ★★ TECHNICAL SKILLS: • Programming Languages: Ruby, Rails, Python, JavaScript, HTML. • Frameworks: Ruby on Rails, Odoo. • Libraries:React JS, Bootstrap, jQuery. • Databases: MySQL, PostgreSQ, Redis. • Test Frameworks: Capybara, RSpec, Jest. • Integration: REST, JSON, YAML, Redis, Graphql. • Administration: Jira, Heroku, Jenkins, AWS. • Operating Systems: Linux & Unix. • Version Control Tools: Github, Bitbucket. • Design Patterns: MVC, MC. • Others: Data Migration, Debugging. I AM HERE! I'd be glad to join your team! Feel free to contact me anytime! Thank you! Khaled Zaher

Delivering systems that scale with your business. Long term solutions and reliability. WHAT I DO: - Build full-stack web applications with .NET backend and Angular frontend - Maintain and extend existing .NET + Angular systems - Integrate REST APIs, real-time updates (SignalR), and third-party services - Upgrade legacy systems (handled .NET 5→8 and Angular 9→17 migrations) - Implement authentication, role-based access, and secure data flows - Optimize frontend performance (bundle size, load times, lazy loading) RECENT PROJECTS: - Built HR management system for sports federations: .NET Core backend with Angular admin panel (role-based access, approval workflows, multilingual support) - Refactored 140+ Angular components, reducing CSS bundle by 80% and improving page load by 11% - Upgraded 5-year-old Angular system from v9→17 without breaking existing features - Migrated production .NET 5 system to .NET 8 while maintaining API compatibility - Built PostGIS/GeoJSON REST API with Angular map interface for location features - Integrated SignalR for real-time scoring and live UI updates EXPERIENCE: - Worked on 5 corporate projects with large codebases and multiple developers - Deployed .NET Core applications to Windows Server, resolved production issues - Mentored junior developer on backend architecture and Angular best practices TECH STACK: Backend: C#, .NET Core, Entity Framework Core, SQL Server, PostgreSQL, Redis Frontend: Angular, TypeScript, RxJS, NgRx, HTML/CSS, Tailwind, Bootstrap Integration: REST APIs, SignalR, JWT authentication, role-based authorization Tools: Git, Docker, xUnit, Figma→HTML conversion HOW I WORK: I ask questions to understand your current system and future needs. I identify technical risks before writing code. I build stable, maintainable solutions with clear documentation. I provide regular progress updates. If you need one developer who can handle both backend logic and frontend UI — let's talk. 🔒 No gambling, adult content, or alcohol projects.

SUMMARY A results-driven software engineer with over 4 years of experience in full-stack development. He has designed robust relational databases, developed scalable backend architectures and intuitive front-end applications, and optimized distributed systems. Passionate about engineering excellence, system scalability, and user experience, he seeks an opportunity to apply his expertise and grow within a high-impact, innovative team. SKILLS Programming languages: Python, C#, TypeScript, JavaScript Frameworks: ASP.NET Core, Django, Next JS, React Data management: PostgreSQL, MySQL, SQL Server, ElasticSearch Cloud computing: Amazon Web Services, Azure, Digital Ocean Other tools and technologies: Jenkins, Docker, Nginx, BeautifulSoup, Git, Selenium, Redux, Redux-Toolkit, Axios, Webpack, Material UI WORK EXPERIENCE Senior Software Developer (September 2024 - Present) Deloitte, Kenya - Diagnosed and resolved high-priority production incidents by conducting root cause analysis and analyzing logs via Azure Application Insights, reducing system downtime, and improving reliability. - Implemented caching strategies with Azure Cache for Redis, optimizing API response times and minimizing redundant database hits. - Designed and maintained microservices architecture, ensuring high availability and fault tolerance in distributed systems. - Mentored junior engineers, promoting best practices in clean architecture, SOLID principles, and performance tuning. - Led knowledge-sharing initiatives, fostering an inclusive and high-performance engineering culture. - Authored technical documentation, streamlining onboarding and expediting troubleshooting for new developers. Software Developer (March 2021 - July 2024) Vantage Intellica, Kenya - Developed high-performance RESTful APIs using ASP.NET Core, optimizing data ingestion and retrieval from Elasticsearch and PostgreSQL, improving query efficiency. - Built interactive dashboards using React, Material UI, Axios, and Nivo, enabling analysts to visualize complex data and extract actionable insights. - Designed and automated CI/CD pipelines using GitHub Actions and Jenkins, deploying applications to AWS EC2, reducing software delivery time by 60%. - Developed interactive geospatial maps with Leaflet, providing real-time geographical impact analysis based on key business variables. - Integrated drag-and-drop functionality into a DevExpress data grid using React Beautiful-DND, reducing manual data classification effort by 30%. - Scheduled and managed background jobs using Quartz.NET, automating web crawling and data classification tasks, and reducing manual intervention. - Implemented Redux for state management in React applications, ensuring data consistency and enhanced user experience. - Integrated RESTful APIs with front-end components using Axios and Fetch API, ensuring seamless synchronization between client applications and backend services. - Diagnosed and resolved UI/UX bugs while developing reusable React components using Material UI, contributing to technical debt reduction and improved maintainability. - Participated in design sessions, providing architectural insights and contributing to scalable and maintainable system designs.

As a highly motivated and results-driven Software Engineer, I am passionate about delivering innovative, scalable, and efficient solutions tailored to your needs. With a strong command of Full-Stack Development, I specialize in creating robust applications and ensuring exceptional user experiences. My expertise includes: Front-End Development: Crafting dynamic, responsive interfaces using React.js, HTML, CSS, and JavaScript. Back-End Proficiency: Developing secure and scalable solutions with Laravel and Node.js. API Integration: Successfully integrating third-party APIs like SAP, Haball, and custom-built solutions. Geospatial Technologies: Utilizing tools like GeoServer, Leaflet, OpenLayers, and PostGIS for advanced mapping solutions. E-Commerce Optimization: Enhancing user experiences, implementing secure payment gateways, and developing automated billing systems. Data Visualization & BI: Creating dynamic dashboards using Power BI and other visualization tools. Key Skills & Technologies Languages: PHP, JavaScript, SQL Frameworks: React.js, Laravel, Next.js Geospatial Tools: GeoServer, GDAL, Geopandas, ESRI APIs Database Systems: MySQL, PostgreSQL/PostGIS, SQL Server Version Control & Collaboration: GitHub, GitLab, Bitbucket, Jira, Confluence Highlight Projects Real Estate ERP System: Implemented advanced GIS functionality, including property boundary mapping, plot merging, and division. Integrated SAP finance for seamless financial reporting and booking processes. Online Property Verification System (OPVS): Developed a property verification tool ensuring legal compliance and ownership authenticity through comprehensive reports and database integration. Prop Feasibility Mapping: Delivered customer location insights using GeoServer with interactive layers for schools, road networks, and more. Optimized decision-making and route planning. Why Choose Me? With a Master’s degree in Computer Science and a proven track record in delivering impactful solutions, I bring a deep understanding of software engineering, data analysis, and geospatial technologies. My strong problem-solving skills, attention to detail, and passion for innovation make me the ideal partner for your next project. Let’s build something remarkable together. Reach out to discuss your project requirements!

Do you have a challenging project? I can help you. All my Upwork projects for 9 years completed successfully! I architected and built successfully dozens of complex scientific and industrial projects and I support some of my long-term projects for years. Also, you’d find my open source projects on GitHub including someones which are used by Google Inc. and other corporations and universities. I'm an Experienced Data Scientist with a demonstrative history of working in the science and research industry. Skilled in Big and Spatial Data processing, Data Exploration, Data Analysis and Machine Learning. Strong engineering professional with a Master's degree in radio physics and electronics focused on nonlinear real world processes modeling from well-known Russian National Research University (UNN), also known as Lobachevsky University. 20+ years of practice in data science and programming engineering in a wide range of projects: from science research in computational physics to complex software products for the real-world problem solutions. Ask my clients about my data science and time management and communication skills: "Alexey completed a very complex and difficult geostatistical analysis in a very condensed time frame and generated exactly what we needed. Would highly recommend!" "Alexey completed this job effectively and very efficiently! His communication on coding plans and progress was fantastic, and he helped me to meet a tight deadline. I would be happy to work with him again in the future and I very highly recommend him to anyone considering hiring him!!" "Alexey was able to solve mathematically technically difficult project involving implementation of an optimizing algorithm. Did own research and made many valuable suggestions. A great job." "Alexey is a very talented resource. He was able to quickly understand our business problem and provide a working solution the FIRST time. There was no back and forth. He designed the solution to be future proof. Top notch guy!" "Alexey is a super developer. Very responsive and diligent. I truly enjoyed working with him and will hire him again and again." "Does what he says and does it on time. Very strong professional." "Alexey is a contractor of the highest calibre. He completed a large, highly complex project that four other contractors were unable to; completed it on time; and improved the project's initial goals, surpassing our expectations. Alexey was also very communicative throughout the project, and delivered before the deadline. I recommend Alexey without reservation, and look forward to working with him again." Software development and research areas: ✓ Scientific modeling, ✓ Geographical sciences, ✓ Large rasters processing, ✓ Topology analysis, ✓ Computer simulation methods, ✓ Graph algorithms, ✓ etc. Data stores: ✓ Classical SQL databases (PostgreSQL, SQLite), ✓ Spatial extensions for relational databases (PostGIS, Spatialite), ✓ Modern RDF databases (OpenLink Virtuoso), ✓ In-memory data structure stores (Redis), ✓ Science Big Data formats (NetCDF), ✓ Multiband GeoTiff files with spatial attributes, ✓ etc. Programming: ✓ Programming on C (shapelib, geoTIFF, gdal, spatialite, etc.), ✓ Programming on Python (Jupyter notebooks, numpy, pandas, scipy, xarray, gdal, etc.), ✓ Programming on SQL, PL/PgSQL, Tcl, shell scripting, etc., ✓ Unix/Linux/MacOSX development, ✓ etc. 2D/3D visualization: ✓ matplotlib, ✓ Cartopy, ✓ QGIS, ✓ VTK/Paraview, ✓ etc. And I develop Open Source Satellite Interferometry (InSAR) processor PyGMTSAR which is user-friendly and scalable parallel Big Data analysing system using state-of-the-art Machine Learning techniques. See on Google Colab, GitHub and DockerHub in Portfolio section. My book “PyGMTSAR: Sentinel-1 Python InSAR: An Introduction” is available on Amazon, Apple, Kobo and many other bookstores for students, researchers, or industry professionals.

I am a highly skilled GIS Developer with a proven track record of delivering impactful spatial data solutions for social good, agriculture, and business intelligence. My expertise lies in leveraging the full stack of geospatial technology from ArcGIS, QGIS, and Google Earth Engine for analysis to Python, JavaScript, and Flask for building custom web applications and APIs. My strength is in transforming complex data into clear, actionable insights and tools. I have successfully applied AI and Machine Learning to real-world challenges, such as crop yield prediction and credit card fraud detection, and I am proficient in data science environments like Jupyter Notebook, Google Colab, and VS Code. Here are highlights of my key projects and accomplishments: 1. Agricultural Intelligence: Developed a Machine Learning-based system for crop yield estimation and classification for small-scale farmers. 2. Web Mapping & Dashboards: Built interactive web maps (using Leaflet/OpenLayers) and GeoNode dashboards for projects like monitoring irrigation schemes and mapping Nairobi's health facilities, enabling efficient resource allocation and water management. 3. Business & Social Impact GIS: Conducted geospatial business intelligence for clients, including pharmaceutical market analysis and customer segmentation for an online business. I also created Python scripts for route optimization, significantly improving delivery efficiency. 4. AI & IoT Innovation: Engineered a smart flight recommender system using AI and developed an IoT tool for real-time farm monitoring. I have also built an agricultural chatbot using RAG and OpenAI and models for real-time crop and weed detection. 5. Remote Sensing & Analysis: Managed remote sensing projects including air quality monitoring, soil moisture analysis, and a flood simulation for Tana River County, contributing to risk reduction and environmental management. Technical Toolkit: - GIS & Remote Sensing: ArcGIS, QGIS, GEE, Google Earth Pro, PostGIS, GeoServer, GeoNode - Programming & AI/ML: Python, R, JavaScript, TensorFlow, Keras - Web Development: Flask, HTML, CSS, Leaflet, OpenLayers - Data Science & Visualization: Jupyter, Google Colab, Power BI, Superset, Excel - Databases: PostgreSQL, PostGIS I hold a BSc in Geospatial Engineering and am certified in Data Science, AI, and Web Development. I am passionate about using my skills to solve complex problems and am eager to bring my blend of technical expertise and project leadership to your next project.

🚀 Senior Software Engineer | Backend Architect | Performance Optimization Expert With 15+ years of experience in software development, I specialize in designing and optimizing high-performance backend systems using Java, C, C++, and Spring Boot. I focus on creating scalable and maintainable solutions for mission-critical systems. Key Skills: Java, C, C++, Spring Boot, Kubernetes, Kafka, MySQL, Docker, CI/CD, and Cloud Deployments. Proven expertise in optimizing system performance (e.g., reduced response times from 500ms to under 50ms). Experienced in building microservices architectures and implementing best practices in DDD and Clean Architecture. Success Stories: ✅ Optimized a microservice for a SIEM platform, improving data processing from 60TB/day with enhanced fault tolerance. ✅ Designed a multi-cloud backup system, ensuring robust data redundancy and disaster recovery. ✅ Developed secure systems with strong encryption, achieving FedRAMP, NIST, and FIPS compliance. 🔎 If you're looking for a highly experienced engineer to optimize performance, improve scalability, or enhance system security, let's connect!

Are you seeking to unlock your organization's true potential through data-driven decision-making? Look no further! 🚀 Upwork Expert-Vetted | Top Rated | Top 1% Talent As an MIT/Harvard MBA-holding Data Science and Engineering Expert, I am passionate about optimizing processes, automating workflows, and deploying cutting-edge ML applications on AWS and Azure for seamless digital transformations. Why Choose Me? 🚀 Machine Learning | Computer Vision | Data Science | NLP | Generative AI ★ Proven Expertise: With a strong foundation in handling big data across diverse domains such as social, market, geospatial, mobility, and healthcare, I deliver actionable insights that drive strategic decision-making. ★ Predictive Modeling: Empower your organization with accurate predictive models that anticipate future trends and opportunities. ★ Web Platform Integration: Seamlessly collect and publish data on web platforms and integrate applications via APIs for increased efficiency and productivity. ★ COVID-19 Forecasting: As part of an esteemed MIT team, I developed a state-of-the-art ML ensemble model for COVID-19 forecasting, successfully implemented by the CDC in early 2021. My Journey and Experience 🚀 11 Years AI Project E2E Development and Deployment at Fortune 500 Companies Education: PhD in BioMedical Engineering, University of Maine MBA, MIT Sloan School of Management (cross-registered at Harvard University) ★ NASA Collaboration: Developed a NIR blood chemistry device for NASA, leading to several patents and a successful start-up exit ★ AI Innovation at Scale: Led machine vision and AI innovation initiatives at industry giants like Bayer and McCain Foods, delivering cutting-edge AI-enabled products to farmers, manufacturers, and consumers. Areas of Expertise Data Science: Python, SQL, R for data analysis, visualization, and modeling. Machine Learning: TensorFlow, Scikit-Learn, PyTorch for building robust ML solutions. Data Engineering: Spark for efficient data processing and transformations. Cloud: AWS, Azure, GCP for scalable and cost-effective cloud-based solutions. Web Development & Automation: HTML, CSS, JavaScript, Flask, Selenium for data mining, publishing, and web automation. API Integration: Seamless integration of applications through APIs for enhanced functionality. Advanced Capabilities: GPT chatbot agent prototyping with plugins and offline text corpus; document summary generation. Testimonials Tyler Fox, COO, BTA Sports (Sports Analytics Startup) "One of the standout qualities of working with Boyan was his proactive approach to problem-solving. He anticipated potential issues, offered creative solutions, and executed them flawlessly. This proactive mindset not only saved time but also added value to the project. I would not hesitate to work with Boyan again in the future. His professionalism, expertise, and dedication to delivering exceptional results make him a standout freelancer. If you are looking for someone who can get the job done efficiently and effectively, Boyan is the freelancer to hire. I highly recommend him for any project, and I am looking forward to our next collaboration."

Hi, I’m a GIS & Full Stack Developer specializing in building interactive mapping platforms, geospatial applications, and scalable web/mobile solutions. I don’t just create maps, I build complete systems that help businesses visualize, analyze, and interact with spatial data in meaningful ways. 🚀 What I Can Do For You: ▪️Build interactive maps using Mapbox, Leaflet, and modern GIS tools ▪️Develop full-stack GIS platforms (React, Node.js, PostgreSQL/PostGIS, ClickHouse) ▪️Create mobile apps with React Native integrated with geospatial features ▪️Design custom dashboards for location-based insights ▪️Implement geo-fencing, H3 indexing, and spatial analytics ▪️Integrate real-time data, APIs, and cloud services (AWS / Azure) 🛠️ My Tech Stack: ▪️Frontend: React, Angular, Mapbox GL JS ▪️Backend: Node.js, Django ▪️Mobile: React Native ▪️GIS: ArcGIS, QGIS, PostGIS, GeoJSON ▪️Cloud & Data: AWS, Azure, ClickHouse, PostgreSQL 💡 Why Clients Work With Me: ▪️I combine GIS expertise + full-stack development (rare combination) ▪️I focus on performance, scalability, and clean UI ▪️I understand both technical implementation and business needs ▪️I deliver end-to-end solutions, not just isolated features If you’re looking to build a modern, scalable, and user-friendly geospatial solution, let’s connect.