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Oscar Bartolome Valdez Sarubbi
AI-Driven Full Stack Engineer: RAG, LLM APIs and Cloud-Native Delivery
SUMMARY
AI-driven engineer with production RAG experience and cloud-native deployment. 5+ years building web and mobile products with React, Vue.js, Laravel, Django, Ionic, and ASP.NET. Shipped a retrieval-augmented assistant using LangChain, vector databases, and LLM APIs to ground answers in internal documents and reduce hallucination. Comfortable across the stack: designing async APIs, owning PostgreSQL and SQL Server schemas, and deploying containerized services with Docker and CI/CD. AWS-certified (Cloud Essentials, Architecting Solutions, Data Lakes). Based in Paraguay (UTC-3/UTC-4) with flexible overlap for US and Canada teams. Open to relocation, preferably within LATAM.
SKILLS AND TECH
  • AI & LLM: RAG, LangChain, Agentic Programming, Tool / Function Calling, LLM API Integration, Prompt Engineering, Vector Databases (ChromaDB), NLP, Hermes (open-source LLM tooling).
  • Back-end: Django, Django REST Framework, Laravel, ASP.NET, Express, REST API Design, OpenAPI, GraphQL.
  • Front-end: React, Next.js, TypeScript, Vue.js, Tailwind, Bootstrap, Framer Motion, React Native, Ionic, Expo, TanStack Query.
  • Databases: PostgreSQL, PostGIS, SQL Server, Redis, Vector Stores.
  • Languages: Python, TypeScript, JavaScript, C#, VB.NET, C/C++, PHP, SQL, Bash, Nix.
  • Tools & Practices: Clean Architecture, Clean Code, Docker, Docker Compose, Domain-Driven Design, Git, GitLab CI, OpenCode, Proxmox, Scrum, Telecommunications, Testing, Virtualization.
  • Operating Systems: Windows, Linux, Ubuntu, Arch, macOS.
  • Editors: VS Code, Vim, Neovim.
LANGUAGES
  • English: Professional Working Proficiency (B2). Comfortable leading technical discussions, writing documentation, and collaborating in English-speaking engineering teams
  • Spanish: Native
EXPERIENCE
Helpers SA Lead Developer — Present
Asuncion, Paraguay https://www.helpers.com.py/
  • Lead a team of 4 engineers delivering a B2C services platform on Laravel, Vue.js, and PostgreSQL. Owned architecture, code review, and release readiness.
  • Replaced blocking request/response flows with asynchronous, queue-based processing using Redis and Laravel Horizon, decoupling long-running sync jobs from user-facing latency.
  • Defined API contracts and integration patterns (versioning, error envelopes, validation) that aligned web, mobile, and backend services around a single source of truth.
  • Built and maintained GitLab CI/CD pipelines with Docker to standardize build, test, and deploy across environments.
  • Shipped and maintained production mobile features in Ionic, React, and TypeScript, coordinating with product and design on UX-driven API changes.
BIX SA Cross-Platform Developer
Asuncion, Paraguay https://www.bixparaguay.com/
  • Rebuilt a mobile application end-to-end with Ionic, React, and TypeScript, improving maintainability and shortening the release cadence for product iterations.
  • Refactored and extended Laravel REST APIs to support new mobile workflows, introducing cleaner domain boundaries between controllers, services, and data access.
  • Standardized request validation, error handling, and response envelopes across endpoints, reducing client-side defensive code and integration bugs.
  • Partnered with product and design to translate UX requirements into consistent API behavior and well-documented contracts.
Softec SRL Full Stack Software Developer
Asuncion, Paraguay https://softec.com.py/
  • Built and maintained location-based applications with React, Django, PostgreSQL, and PostGIS, including geospatial queries for proximity and routing features.
  • Designed and shipped REST APIs with Django REST Framework and OpenAPI documentation, giving web and mobile clients a clear, self-describing contract.
  • Modeled relational schemas and wrote SQL for transactional modules, reporting workloads, and cross-system integrations.
  • Containerized services and built GitLab CI/CD pipelines to bring existing codebases to reproducible, automated deploys.
  • Designed and implemented a RAG assistant over internal documentation: chunked source documents, generated embeddings, indexed them in a vector store, and orchestrated retrieval-augmented prompts via LangChain and LLM APIs to ground answers and reduce hallucination.
  • Tuned the retrieval pipeline around chunk size and overlap, prompt grounding, and provider/model selection to balance answer quality against inference latency and cost.
  • Shipped real-time in-app chat over WebSockets with Django Channels, supporting presence and message persistence.
  • Designed and implemented electronic invoicing and SAP HANA integrations across .NET codebases in C# and VB.NET, backed by SQL Server. Owned service-layer design, data flows, and integration with corporate systems.
PROJECTS
Faculty Chat Bot:
  • Built a chatbot with Rasa Open Source and a custom NLU pipeline, defining intents, entities, and dialogue policies to handle student queries end-to-end.
  • Implemented a Python backend with PostgreSQL for conversation persistence, user state, and analytics.
  • Applied Transformer-based NLP techniques to improve intent recognition and response quality over baseline keyword approaches.
  • Integrated the Telegram Bot API as a familiar delivery channel for students.
  • Containerized the full stack with Docker to standardize local development and deployment.
Personal Blog:
  • Built a performant static site with Astro.js and a Strapi headless CMS backed by PostgreSQL.
  • Modeled content with structured schemas and served it via GraphQL to listing and detail views.
EDUCATION
Universidad Nacional de Asunción
Bachelor's - Electronic Engineering
CERTIFICATES
Cybersecurity Essentials, Cisco Network Academy
AWS Cloud Technical Essentials, Amazon Web Services
Architecting Solutions on AWS, Amazon Web Services
Building Data Lakes on AWS, Amazon Web Services