Reiner Marquez Full-Stack Software Engineer
Profile

Full-Stack Engineer with 15+ years of experience building scalable frontend and backend systems, specializing in Python and SQL optimization. In the past 2+ years, I’ve delivered LLM-base Apps using RAG, MCP, embeddings, and prompt engineering to automate workflows and improve user experience. Strong collaborator in agile environments, with a proven ability to learn fast and ship value-driven products.

Skills
Python / Django / FastAPI
SQL / NoSQL
LLM Integration / RAG Systems / Vector DB / MCP
Javascript / VueJS / NuxtJS
REST APIs
Unit Testing
Professional Experience
  • •Introduced and established Vapi as the orchestration layer for AI voice agents, accelerating prototyping and providing a scalable foundation.
  • •Implemented multiple conversational agents integrated with Twilio, demonstrating end-to-end autonomous call handling and reducing manual workload by ~40% in pilot tests.
  • •Implemented Langfuse as the evaluation and observability layer, improving traceability, reducing debugging time by ~40%, and enabling rapid iteration on agent behaviors.
  • •Designed and deployed a data pipeline to structure and index call transcripts, enabling dynamic prompt generation and projected to increase conversation success rates by ~25%.
  • •Updated the legacy Shopify app to support OAuth authentication, streamlining the auth flow and eliminating unnecessary redirects.
  • •Optimized app architecture for handling Shopify webhooks with celery/rabbitmq, boosting scalability and reducing infrastructure costs by 30% through a switch from Google Pub/Sub to HTTPS.
  • •Led the fixing of issues detected during the Shopify App Review process, which allowed to get the Shopify App approved
  • •Contributed to the resolution of issues identified during the Shopify App Review, resulting in app approval.
  • •Conducted technical interviews as a key part of the recruitment team.
    • Full Stack Developer, QBan Consulting
    06/2022 – 07/2023
  • •Defined and implemented software development best practices: versioned legacy code, adopted GitHub flow and standardized code format with lint tools.
  • •Developed reusable Vue.js components to enhance UI consistency and code maintainability.
  • •Established CI/CD pipeline for streamlined development and deployment processes.
  • •Added new features, resolved critical bugs, and conduct the release of the MVP.
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    06/2021 – 05/2022
  • •Served as Interim Tech Lead, guiding the team through critical phases.
  • •Conducted onboarding for two project members, including a new Tech Lead.
  • •Provided valuable feedback during code reviews, enhancing code quality.
  • •Implemented unit tests, increasing code coverage to over 90% and improving reliability.
  • •Improved GraphQL API performance by adding DB indexing strategies, optimizing SQL queries and resolving n+1 GraphQL issues.
    • Tech Lead, Zehnergroup
    04/2012 – 07/2020
  • •Led the technical team while handling both backend and frontend development and managing DevOps processes
  • •Conducted technical interviews to identify and recruit qualified candidates
    • Open Source Contributions
  • •Add support for agent-wide dynamic tool filtering or modification before sending to the model, with access to the run context - PR
  • •Implemented Application handler for Webz API - PR
  • •Implemented a copier template to generate boilerplate code for new MindsDB's handlers - Repo
    • Projects

    Pydantic AI - Logfire - FastAPI - LLM - Telegram Bot API

    Options Explorer, An options analysis tool that gives traders deeper insights to improve strategies.

    Streamlit - DuckDB - Apache Parquet - Polygon API

    Certificates
    Languages
    Spanish — C2English — B2
    Hobbies
    Solving puzzlesBoard gamesWorking out
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