Building web apps, automations and AI systems that are fast, reliable and conversion-focused.
I'm Gabriel Barreto, a full-stack developer from Brazil, based in Portugal. Across 50+ projects I've helped businesses and agencies build web apps, automations and AI systems that actually ship — direct, by text, delivered fast. I work with clients across Europe and Latin America, in English, Portuguese and Spanish.
A sales funnel in four languages for an AI receptionist aimed at clinics — with a working conversational demo you can talk to on the page. The assistant answers scheduling questions in the visitor's language, keeps context across the conversation, and replies in under a second.
Bots with AI + payments — essay grading, astrology & tarot. Thousands of messages, monetized via Telegram Stars.
Custom online stores with checkout, admin and catalog management — from concept to deployed.
Largest: 503 commits · 123 API routes · Stripe and Mercado Pago in parallel · end-to-end tested
Internal tools, admin panels and company intranets — auth, roles, reporting and data at scale.
Largest: 123 API routes · 235 TypeScript files · role-based access, PDF and Excel export
Property listing platforms and marketing sites with search, filters and lead capture.
WhatsApp/Telegram automations, schedulers, scraping and workflow pipelines that run unattended.
Includes an Amazon SP-API pipeline running unattended across separate seller accounts
Amazon SP-API migration & reconciliation →Tools around advertising and marketplaces — reliable and built to scale with volume.
Custom automation for online games — complex logic and resilient long-running processes, sold to real users.
LLM-powered assistants embedded in real products — answering, qualifying and acting, not just chatting.
Websites, web apps, dashboards, SaaS and e-commerce — built with Next.js, React and Node. Clean, fast and made to scale.
WhatsApp & Telegram bots, integrations, scraping and workflow automation. I remove the manual work so the business runs on its own.
AI agents, chatbots and assistants plugged into real products — from idea to a working, useful feature, not a demo.
Robust APIs, databases and back-ends with Node/NestJS and Python — the reliable engine behind serious products.
Tell me the problem by text — no endless calls. I come back with a clear plan, timeline and a fixed quote.
You get regular updates and something working early. Full visibility, no surprises along the way.
Shipped, documented and handed over — white-label if you prefer. I stay available afterwards.
Tell me what you need and I'll come back with a plan and a quote — fast, by email or WhatsApp.
Contact me ↗