Annas K.

I help founders and businesses build, launch, and improve SaaS products and full-stack web applications. Whether you're starting a new product, scaling an existing platform, or dealing with backend and integration challenges, I can take ownership of the engineering work from architecture through development and deployment. I'm a Senior Full Stack Developer with 12+ years of experience, Top Rated Plus on Upwork, with $80K+ in earnings and experience across SaaS platforms, business applications, APIs, payment systems, and custom software. WHAT I CAN BUILD FOR YOU SaaS Applications & MVP Development Build new SaaS products, multi-tenant applications, subscription platforms, customer portals, dashboards, and business management systems. I can help turn your product requirements into a well-structured, production-ready application. Full-Stack Web Application Development Develop modern web applications using React, Next.js, Node.js, TypeScript, and JavaScript. Whether you need a new application or want to extend an existing codebase, I focus on functionality, maintainability, performance, and a smooth user experience. Backend & API Development Build Node.js backend systems, REST APIs, authentication, authorization, role-based access control, database architecture, and third-party integrations. I can also help troubleshoot existing systems and improve application architecture. Stripe & Payment Integration Implement Stripe Checkout, recurring subscriptions, payment workflows, webhooks, subscription lifecycle management, renewals, cancellations, and failed-payment handling. I focus on making billing reliable and manageable as your product grows. Business & Healthcare Software Develop CRM platforms, internal business tools, operational dashboards, onboarding systems, workflow automation, and healthcare software. My experience includes complex workflows, secure access controls, audit trails, and multi-facility management. AI-Enabled Applications Integrate OpenAI APIs and practical AI-powered features into new or existing applications, including intelligent workflows and document-oriented functionality. SELECTED PROJECT EXPERIENCE CRM & Sales Management Platform Developed a full-stack CRM application for managing leads, customer interactions, sales pipelines, activity tracking, and reporting, with authentication and role-based access. Healthcare Operations SaaS Platform Developed an operations platform covering onboarding, compliance workflows, incident reporting, document generation, e-signatures, audit trails, and multi-facility management. Stripe Subscription & SaaS Billing Platform Turned a React application into a subscription-ready SaaS product, integrating Clerk authentication, Stripe subscription billing, and Vercel deployment. The project also included technical documentation and a structured handover so the client could independently manage the application and its infrastructure. MY CORE TECHNOLOGIES Frontend: React, Next.js, TypeScript, JavaScript Backend: Node.js, REST APIs, API Integration Databases: PostgreSQL, MySQL, MongoDB Payments: Stripe, Stripe API, Subscription Billing Cloud & Deployment: AWS, Docker, Vercel AI Integration: OpenAI API WHAT YOU CAN EXPECT I take time to understand your product, business requirements, existing architecture, and the problems you're trying to solve before deciding how to approach the implementation. You'll get direct technical communication, thoughtful engineering decisions, maintainable code, and clear documentation. I also consider security, scalability, deployment, and long-term ownership rather than focusing only on getting features completed. Have a SaaS product to build, an existing application to improve, or a backend or Stripe integration to implement? Share what you're working on and where you need help. I'd be glad to understand your requirements and discuss the right technical approach.