I'm a Senior Software Engineer and SaaS Architect with 15+ years delivering production-grade platforms across FinTech, hospitality, healthcare, aviation, and AI. I've built 23+ live products as a solo full-stack developer, including multi-tenant SaaS systems, cross-platform Flutter apps, WhatsApp Business automation platforms, and AI chatbot integrations. I own the full stack: Flutter mobile, React/Next.js frontend, Node.js backend, PostgreSQL/Supabase data layer, and cloud deployments on Railway/Vercel. I collaborate with clients globally as a freelancer on Upwork and People Per Hour.

Juan Diego Montero

I'm a Senior Software Engineer and SaaS Architect with 15+ years delivering production-grade platforms across FinTech, hospitality, healthcare, aviation, and AI. I've built 23+ live products as a solo full-stack developer, including multi-tenant SaaS systems, cross-platform Flutter apps, WhatsApp Business automation platforms, and AI chatbot integrations. I own the full stack: Flutter mobile, React/Next.js frontend, Node.js backend, PostgreSQL/Supabase data layer, and cloud deployments on Railway/Vercel. I collaborate with clients globally as a freelancer on Upwork and People Per Hour.

Available to hire

I’m a Senior Software Engineer and SaaS Architect with 15+ years delivering production-grade platforms across FinTech, hospitality, healthcare, aviation, and AI. I’ve built 23+ live products as a solo full-stack developer, including multi-tenant SaaS systems, cross-platform Flutter apps, WhatsApp Business automation platforms, and AI chatbot integrations.

I own the full stack: Flutter mobile, React/Next.js frontend, Node.js backend, PostgreSQL/Supabase data layer, and cloud deployments on Railway/Vercel. I collaborate with clients globally as a freelancer on Upwork and People Per Hour.

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Experience Level

Expert
Expert
Expert
Expert
Expert
Expert

Language

English
Fluent
Spanish; Castilian
Fluent

Work Experience

Senior Software Engineer & SaaS Architect at Freelance (Upwork / People Per Hour)
January 1, 2009 - Present
Full ownership of architecture, backend, frontend, and mobile layers across 23+ production platforms. Built 9+ multi-tenant SaaS platforms with org-level data isolation, RBAC, and subscription billing. Developed REST APIs in Node.js/TypeScript with PostgreSQL and Supabase, including RLS-based tenant separation. Created 10+ Flutter mobile apps for iOS and Android with offline capabilities and location features. Integrated AI providers (OpenAI, Claude, Gemini) into workflow automation and chatbot products. Implemented WhatsApp Business Cloud API integration, webhook handling, and multi-step chatbot flows. Delivered Stripe Connect payment flows and multi-tier subscription billing. Deployed on Railway / Vercel with CI/CD pipelines.

Education

Bachelor of Science in Computer Engineering (BSCpE) at Florida International University
April 11, 1993 - October 18, 1997

Qualifications

Add your qualifications or awards here.

Industry Experience

Software & Internet, Financial Services, Healthcare, Travel & Hospitality, Professional Services