Hire the Best API Developers
in Kenya

I am a senior integrations expert specializing in: 1. Microsoft Graph API - any integration for the entire Microsoft 365 ecosystem. I build connections between Teams, Outlook, SharePoint, and OneDrive, automating document processing, calendar syncing and organizational workflows with external systems, applications and CRMs. 2. POS Systems & Specialized Software - development of POS systems like the Qulah - restaurant POS system, focusing on reliability, offline-first capabilities, and seamless user experiences. 3. Full Stack Developer - With over 10 years working with Laravel, Python and Nodejs, I ensure that frontend interfaces are intuitive while back-end architectures are secure, scalable, and maintainable. 4. Global Payments and API Integrations - I have extensive experience implementing complex payment gateways across diverse platforms, including Stripe, Paddle, Paystack, and M-Pesa. Clients work with me when they need more than just a developer; they need an architect who understands business needs and create applications their pain points. Whether it is building custom middleware, syncing CRM processes, or developing and deploying AI-powered workflows, I focus on delivering production ready solutions that bring value to my clients and their stakeholders. With over 10 years of experience (over 70 jobs, over 6000 hours and over USD 200,000 in earnings here on Upwork alone - which speaks of the trust my clients have with my delivery) in both small, medium and enterprise applications, I bridge the gap between complex business requirements and high performance technical solutions. Education wise, I hold an undergraduate degree in Computer Science and a Master’s in Information Systems, providing a deep academic and practical foundation for every project I undertake. Engage me anytime for your project and I look forward to bringing value to your business.

I’m a Senior Full-Stack Engineer with extensive experience building reliable, scalable web applications from the ground up. I help clients turn complex ideas into production-ready systems that are fast, maintainable, and built to last. I specialize in working across the stack — from well-designed backend APIs and data models to clean, responsive front-end interfaces — with a strong emphasis on code quality, performance, and real-world reliability. What I bring to your project: 1. Backend expertise: Node.js, TypeScript, REST APIs, background jobs, data synchronization, third-party integrations 2. Frontend expertise: modern JavaScript frameworks, clean UI architecture, responsive and user-friendly interfaces 3. System design: scalable architectures, clear API contracts, and maintainable codebases 4. Problem-solving: breaking down ambiguous requirements, handling edge cases, and delivering practical solutions 5. Ownership: I take responsibility for features end-to-end, not just isolated tasks I’m particularly strong at projects that require: - Integrating multiple services or APIs - Handling complex business logic or data flows - Improving or stabilizing existing systems - Building MVPs that are ready to scale Clients appreciate working with me because I communicate clearly, think ahead, and deliver dependable results without constant hand-holding. If you need a senior engineer who can quickly understand your product, make solid technical decisions, and execute with precision — I’d be glad to help.

I am an AI enabled Senior Developer who bridges the gap between complex Full-Stack engineering and conversion-focused E-commerce. Whether it’s architecting a custom RAG pipeline or AI workflow for your SaaS, or building a headless Shopify store that loads in under 2 seconds, I ship production-ready code that drives measurable growth. PROVEN IMPACT The New York Times Store & JR Dunn: Engineered high-traffic production solutions. Performance: Delivered 40% Core Web Vitals improvement and 25% faster page loads. Efficiency: Reduced AI token costs by 30% through optimized prompt engineering and RAG caching. WHAT I DELIVER AI & Intelligent Systems Custom LLM integrations (OpenAI/Claude) RAG pipelines with LangChain AI agents that automate customer workflows and data processing Shopify & Headless Commerce Custom Liquid themes Hydrogen (Next.js) builds Complex API integrations (Stripe, Klaviyo, ERPs) designed for high-volume scale Full-Stack SaaS Development End-to-end platforms using React/Next.js and NestJS/Node.js or Java springboot/Python Flask Clean, type-safe architectures (TypeScript) that don't accrue technical debt CORE TECH STACK Frontend: React, Next.js, Remix/ReactRouter, TypeScript, Tailwind CSS, Figma-to-Code Backend: Node.js, Python, Java, NestJS, Laravel, PostgreSQL, Prisma AI/Automation: LangChain, OpenAI API, Anthropic,N8N Vector DBs (Neo4j/Pinecone), n8n I take full ownership of the lifecycle, from technical discovery to deployment. Invite me to your project , I’m available now and can provide a technical roadmap within the hour. KEYWORDS Full Stack Developer | Shopify Developer | Shopify Liquid Developer | Headless Commerce | Shopify Theme Development | E-Commerce Developer | React Developer | Next.js Developer | NestJS Developer | Node.js Developer | Laravel Developer | PHP Developer | TypeScript Developer | AI Integration Developer | LangChain Developer | OpenAI API | Anthropic Claude API | GraphRAG | Magento Developer | React Native Developer | Mobile App Developer | API Developer | REST API | GraphQL | SaaS Developer | Web Application Developer | Frontend Developer | Figma to Code | Performance Optimization | Core Web Vitals | Docker | AWS | Vercel | PostgreSQL | MongoDB | Firebase

Hello, I am Collins Marvin, a professional software engineer with 7 years of experience in software development specializing in fullstack web applications. I've successfully completed trustworthy, scalable, robust and secure web applications and solved clients' problems in a more efficient way by understanding their problems. My languages of trade are PHP and/or Golang for backend, JS,VueJS, and CSS,TailwindCss for frontend. I also enjoy using PHP and Golang frameworks to speed development. I am comfortable working with different timezones, can easily integrate with any team, and deliver quality solutions with a lot of honesty. My Skills - PHP,Laravel - Golang - JS,VueJS,ReactJs - HTML,CSS,TailwindCSS,Bootstrap - AWS,DO,Linode,GCP,VPS Management - MYSQL,CockRoachDB,PostgreSQL,SQLite,MongoDB,MSSQL,Redis - CI/CD (Gitlab, Github, Bitbucket) - Deployment and release engineer - TDD,DDD,BDD - Responsive website design - Server management - Restfull API design and development - GraphQL - gRPC - Design patterns - Git Versioning - Ansible - Relational Database Management - Markdown,YML file - Docker I hope to work with you.

I help clients with Python-based API work, web scraping, automation, and data processing. Most of my work has involved: – Consuming and integrating APIs (Twitter/X, YouTube, third-party services) – Scraping and cleaning large datasets – Automating data pipelines and scripts – Building small web tools and dashboards I specialize in short-term, clearly scoped projects where you need something built, fixed, or automated without long onboarding. Tools I use regularly: – Python (requests, pandas, automation scripts) – APIs & webhooks – PostgreSQL / Google Sheets – React (for lightweight frontends when needed) I value clear communication, fast turnaround, and realistic scope. If your task fits that, I’m happy to take a look.

Backend & API Developer specializing in C#/.NET, integrations, automation systems, and scalable business applications. I help businesses build, extend, fix, and stabilize backend systems that are critical to daily operations including SaaS platforms, CRMs, enterprise tools, workflow systems, desktop applications, and API-driven platforms. A large part of my work involves joining existing systems, understanding complex workflows quickly, and implementing solutions without breaking current operations. Core areas I work on: • REST API development & third-party integrations • OAuth, JWT, API authentication & secure system communication • Payment gateway, CRM, ERP, Shopify, and external service integrations • Workflow automation & background job processing • SQL Server, MySQL & PostgreSQL database design and optimization • Backend architecture and business logic implementation • System synchronization, offline/online sync flows & webhook handling • Performance optimization, debugging & legacy system stabilization • Desktop and web application backend development Technologies I work with regularly: • C# • ASP.NET Core / .NET Framework • Entity Framework Core • SQL Server / MySQL / PostgreSQL • Python • JavaScript • REST APIs • Laravel integrations • Queue systems & background processing I’m comfortable working on: • existing production systems • partially completed projects • unstable integrations • legacy applications • complex operational workflows • multi-module business platforms Recent work includes: • Migrating SOAP integrations to REST/OAuth architectures • Fixing broken third-party API integrations • Building and optimizing backend workflows • CRM and operational platform integrations • Authentication and secure API communication systems • Business process automation tools • Backend systems for finance and operational management • Performance optimization for API-heavy systems What clients value most when working with me: • fast understanding of technical problems • reliable communication • maintainable implementations • clean and structured backend logic • safe integration into existing systems • practical solutions focused on business outcomes If you need a developer who can understand the system, identify the actual problem, and implement a reliable solution without unnecessary complexity, I’m ready to help.