Harper

Full Stack Web Developer & API Integration Specialist

Self-Employed / Freelance • Freiberufler

Mar 2026 - Present • 2 mos

Specialized in API integrations, backend systems, and SaaS platform development. Successfully delivered Meta (Facebook & Instagram) Graph API integration for MASS, a martial arts school management SaaS platform, including OAuth authentication, automated social media publishing, webhook implementation, and multi-tenant support. Also built LinkedIn OAuth integration and video publishing features. Experienced with Deno backend, React frontend, Stripe payments, and Base44 platform development.

AI Chatbot & Automation Developer

Self Employed • Freiberufler

Dec 2024 - Present • 1 yr 5 mos

Developed AI-powered chatbot systems and business automation workflows for client platforms. Integrated OpenAI-powered conversation flows with messaging channels including Facebook Messenger, Instagram DMs, and WhatsApp Business. Built automated lead capture, customer response, and appointment booking systems that reduced manual workload by over 60% for business owners.

Multi Tenant Saas Platform Developer

Micarrt Unity • Selbstständig

Aug 2023 - Present • 2 yrs 9 mos

Architected and developed multi-tenant SaaS platforms where multiple businesses operate independently within a single application. Implemented tenant isolation, role-based access control, subscription management, and usage limit enforcement. Built onboarding flows, billing integration, and admin dashboards that allowed SaaS founders to launch and scale their products confidently.