Sfoglia categorie
Esplora
Fiverr Pro
Italiano
$
USD
John F.
@john_frantzis
Grecia
Inglese
Chi sono
Full-stack SaaS & AI engineer building production systems end-to-end.
I design scalable architectures, implement multi-tenant backends, and ship revenue-driven automation using TypeScript, Node.js, React and PostgreSQL.
Specialized in:
• AI agents for voice, email and workflow automation
• Stripe billing & subscription lifecycle
• Secure integrations (REST APIs, webhooks, async jobs)
• Real-time dashboards & analytics
• Supabase with RLS and Edge Functions
I turn complex product ideas into fast, stable and monetizable platforms.
Competenze
John F.
offline •
Consulta i miei servizi
Applicazioni web full stack
I will build your saas mvp from idea to production
Automazioni e agenti
I will build ai agents for automation and ai phone call systems
Portfolio
Esperienza lavorativa
Invoice-Lens.com
Invoice lens • Lavoratore autonomo
Aug 2025 - Present • 9 mos
Founder & Lead Full-Stack Engineer behind a production AI SaaS platform for invoice automation and revenue recovery. Architected and developed the system end-to-end: multi-tenant backend, secure PostgreSQL database with RLS, Stripe subscription lifecycle, real-time financial dashboards and async event processing. Built AI agents for voice, email and operational workflows that analyze customer data, trigger automated actions and generate next-best-action insights. Implemented complex integrations (payment providers, external APIs, webhooks), background jobs, retry logic, audit logs and role-based access. Designed the product for real business usage with scalability, observability and performance in mind. Tech stack: TypeScript, Node.js, React, Supabase, PostgreSQL, Edge Functions, LLM APIs.
