I'm a Senior Software Engineer and SaaS Architect with 15+ years delivering production-grade platforms across FinTech, healthcare, hospitality, aviation, and AI. I pride myself on building scalable, multi-tenant systems and end-to-end solutions from concept to deployment. As a solo freelancer on Upwork and People Per Hour, I own the full stack: architecture, backend, frontend, mobile, and cloud deployments. I've shipped 23+ live products, including multi-tenant SaaS platforms, Flutter apps, WhatsApp automation, and AI chatbot integrations.…

Juan Diego Montero

I'm a Senior Software Engineer and SaaS Architect with 15+ years delivering production-grade platforms across FinTech, healthcare, hospitality, aviation, and AI. I pride myself on building scalable, multi-tenant systems and end-to-end solutions from concept to deployment. As a solo freelancer on Upwork and People Per Hour, I own the full stack: architecture, backend, frontend, mobile, and cloud deployments. I've shipped 23+ live products, including multi-tenant SaaS platforms, Flutter apps, WhatsApp automation, and AI chatbot integrations.…

Available to hire

I’m a Senior Software Engineer and SaaS Architect with 15+ years delivering production-grade platforms across FinTech, healthcare, hospitality, aviation, and AI. I pride myself on building scalable, multi-tenant systems and end-to-end solutions from concept to deployment.

As a solo freelancer on Upwork and People Per Hour, I own the full stack: architecture, backend, frontend, mobile, and cloud deployments. I’ve shipped 23+ live products, including multi-tenant SaaS platforms, Flutter apps, WhatsApp automation, and AI chatbot integrations.

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Skills

Experience Level

AI Images
Expert
AI Chatbot
Expert
Web Design
Expert
Tailwind
Expert
Flutter
Expert
Node.js
Expert
React JS
Expert
Dart
Expert
TypeScript
Expert
Android
Expert
PostgreSQL
Expert
Stripe
Expert
Twilio
Expert
n8n
Intermediate
HTML5
Intermediate
React Native
Intermediate
Web3
Intermediate
iOS
Intermediate
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Language

English
Advanced
Spanish; Castilian
Fluent

Work Experience

Senior Full-Stack Developer at Freelance/Self-Employed
January 1, 2009 - Present
Architect and develop production-ready SaaS platforms for diverse industries, specializing in building scalable business applications with sophisticated user management and real-time workflows.
Senior Full-Stack Engineer | SaaS Architect at Freelance
January 1, 2009 - Present
Designed, built, and maintained scalable SaaS platforms with full ownership of frontend architecture, backend services, and data systems. Key projects included multi-tenant systems in various domains, implementing REST APIs, and optimizing PostgreSQL databases.
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 for clients in FinTech, healthcare, hospitality, aviation, and AI. Led design of 9+ multi-tenant SaaS platforms with org-level data isolation, RBAC, and subscription billing. Built scalable REST APIs in Node.js/TypeScript with PostgreSQL and Supabase, including Row-Level Security (RLS) enforced tenant separation. Developed 10+ Flutter mobile apps for iOS and Android with offline support and location awareness. Integrated AI providers (OpenAI, Claude, Google Gemini) into workflow automation and chatbot products. Implemented WhatsApp Business Cloud API end-to-end including webhook ingestion, session management, and chatbot flows. Delivered Stripe-based payment flows and tiered subscription billing for marketplaces and SaaS. Deployed and maintained production apps on Railway, Vercel, and Supabase with CI/CD pipelines and monitoring.

Education

Bachelor of Science in Computer Engineering at Florida International University
January 1, 1993 - January 1, 1997
Bachelor of Science in Computer Engineering (BSCpE) at Florida International University
January 11, 2030 - April 9, 2026

Qualifications

Add your qualifications or awards here.

Industry Experience

Computers & Electronics, Media & Entertainment, Software & Internet, Professional Services, Non-Profit Organization, Healthcare, Financial Services, Education, Travel & Hospitality