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Achievement: Pair Extraordinairex2Achievement: YOLOAchievement: QuickdrawAchievement: Pull Sharkx2

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alejo86a/README.md

Hi, I'm José Alejandro Berrío Marín 👋

Project Lead at Mercado Libre (Mercado Pago) · 9+ years building fintech platforms across Latin America · Based in Medellín, Colombia 🇨🇴

I lead engineering teams that ship high-scale payment and fintech products — most recently a QR payment solution that scaled from 0 to 1M+ monthly transactions in 2 months. Before moving into leadership, I spent years as a Node.js backend developer, and I'm currently a candidate for a Master's in Data Science, which is why you'll see a mix of production backend work and ML/data projects in my repos.

  • 🔭 Currently leading engineering at Mercado Pago, and exploring applied ML/Data Science
  • 💳 Background in fintech: Mercado Pago, Rappi/RappiPay, Rapicredit, Leal, SURA
  • 🧠 Transitioning technical depth from backend systems → data science & ML
  • 🌱 Interests: AI agents / coding agents, machine learning, system architecture
  • 🌎 Languages: Spanish (native), English (fluent), Portuguese (intermediate)
  • 📫 Reach me: alejo86a.com · LinkedIn · info@alejo86a.com

Experience highlights

Company Role Impact
Mercado Libre / Mercado Pago Project Lead (9-engineer team) Launched QR payments, scaled to 1M+ monthly transactions
Leal Technical Leader (7-engineer team) Loyalty platform serving 1M+ users across 8 countries
Rappi Backend Engineer Co-created RappiPay, first co-branded credit card w/ Davivienda, 100K+ users
Rapicredit Backend Engineer Java/Spring Boot risk-scoring APIs

Tech I work with

Backend: Node.js, TypeScript/JavaScript, Java, Go, Python, PHP Data/ML: Python, pandas, scikit-learn, Jupyter Cloud/DevOps: AWS, Kubernetes, Docker, Terraform, Kafka Databases: PostgreSQL, MySQL, DynamoDB, Redis Frontend: React, Angular, Vue, Next.js

Pinned projects

Check out my pinned repos below — ranging from backend/infra tooling to Data Science coursework and applied ML (fraud/accident prediction, bank marketing, etc.) as part of my Master's studies.

⭐️ from alejo86a

Pinned Loading

  1. shiptrack-api shiptrack-api Public

    Logistics package tracking API — Clean Architecture, NestJS, Docker, PostgreSQL, Redis, full CI/CD

    TypeScript

  2. alejo86a.github.io alejo86a.github.io Public

    Personal website and portfolio monorepo for Alejandro Berrío Marín — Project Lead (fintech) and Data Science Master's candidate. Site: alejo86a.com

    HTML

  3. leet-code-excercises leet-code-excercises Public

    Collection of LeetCode questions to ace the coding interview! - Created using [LeetHub](https://github.com/QasimWani/LeetHub)

    JavaScript

  4. machine-learning-evaluacion-final machine-learning-evaluacion-final Public

    Machine learning project (CRISP-DM) predicting bank term deposit subscription, with a Streamlit demo app.

    Jupyter Notebook

  5. machine-learning-class machine-learning-class Public

    Machine learning course exercise: Streamlit app deploying a regression model to predict videogame-store consumer data

    Python