Senior Full-Stack Developer
Ciento LLC
Architected and developed membership, affiliate, payment, dashboard and analytics flows with Next.js, Django, PostgreSQL, Redis and Stripe.
Full-Stack Senior - AI Engineer
I build AI-enabled products, dashboards and automation systems.
I am Rainier Alejandro Contreras Feliz, a Dominican full-stack developer focused on the point where product engineering, conversational AI, cloud infrastructure and business operations meet.
Professional Experience
2025 - Present
Senior AI Engineer
Coyan Services / Coca-Cola Andina
Remote AI engineering role focused on LLM workflows, automation infrastructure, cloud deployment support and production-grade systems.
Full-Stack Developer and AI Automation Engineer
IntelArt
Built AI agents with memory and RAG, n8n/WhatsApp automations, dashboards, APIs and cloud deployments on Hetzner, Coolify and Cloud Run.
Python and Odoo Developer
Ares Seguridad / Atrivia ERP / ONE
Delivered custom Odoo modules, reporting, APIs, WhatsApp/CRM integrations, MQTT connections and data scripts for operational workflows.
Selected Work
Featured GitHub projects
These are the projects highlighted on my GitHub profile, documented with fresh screenshots and clearer technical context.
Built as a clean conversion-oriented Next.js experience with hero messaging, feature cards, sample output, pricing and CTA sections.
Next.jsReactTailwind CSSTypeScript
Shows product thinking, responsive UI and consumer AI positioning.
Receives calls, stores call metadata, transcribes audio and gives operators a protected dashboard to manage complaints, categories, status and follow-up.
Next.jsTwilioWhisperSupabaseTailwind CSS
Demonstrates voice automation, dashboard design and operational workflows.
Combines FastAPI, PostgreSQL and a Next.js admin dashboard for reservations, tables, availability, KPIs and voice/chat booking integrations.
FastAPINext.jsPostgreSQLJWTRecharts
Good example of API design, business logic and frontend operations tooling.
A dense private workspace with PostgreSQL-backed routes, project/task modules, Google Calendar integration paths and AI coordination routes.
Next.jsPostgreSQLOpenAIGoogle Calendarshadcn/ui
Shows full-stack product architecture for a real personal operating system.
Uses an Electron main process, preload APIs, Groq Whisper, SQLite history, clipboard actions and a polished renderer dashboard for reviewing transcripts.
ElectronReactTypeScriptGroqSQLite
Highlights desktop app development, native bridges and AI audio workflows.
A Flask API that uses Playwright/Chromium to render HTML, waits for visual assets, compresses output and prepares the image for object storage.
PythonFlaskPlaywrightPillowMinIO/S3
Useful infrastructure piece for social cards, email previews and automated publishing.
Polls AI RSS feeds, cleans article content, uses an LLM to avoid duplicate stories, stores candidates in SQLite and sends approvals through Telegram.
PythonfeedparserSQLiteOpenRouterTelegram Bot
Shows automation beyond CRUD: ingestion, reasoning, human approval and distribution.
Technical Range
Stack and capabilities
Languages
PythonTypeScriptJavaScriptSQLJava
Frontend
ReactNext.jsTailwind CSSshadcn/uiElectron
Backend
FastAPINode.jsDjangoPostgreSQLRedisSQLite
AI and Agents
RAGLangChainLangGraphLlamaIndexOpenAIGeminiOpenRouter
Voice and Messaging
Twilio VoiceWhatsAppVapiElevenLabsJambonzTelegram Bots
Cloud and DevOps
DockerGoogle CloudAWSAzureHetznerCoolifyMinIO/S3
Contact
Available for AI, full-stack and cloud engineering work.
I work best on products that need real implementation depth: APIs, dashboards, AI agents, voice automation, data workflows and deployment.