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Javier – SQL, AWS, Python, experts in Lemon.io

Javier

From Chile (UTC-3)flag

Data Engineer|Senior

Javier – SQL, AWS, Python

With over 10 years of experience in the industry, Javier is a seasoned Data Engineer with a strong understanding of modern cloud environments and ETL workflows. Throughout his career, he’s managed teams of 4-6 engineers and held a CTO role at a startup. Beyond his core work, Javier contributes to open-source projects and teaches, reflecting his commitment to continuous learning and knowledge sharing.

12 years of commercial experience in
AI
Analytics
Consulting services
Credit and lending
Data analytics
Fintech
Govtech
Open source
AI software
Dev tools
Simulation software
Utilities
Web development
Software development
Main technologies
SQL
13 years
AWS
5 years
Python
9 years
Microsoft Azure
3 years
GCP
4 years
Additional skills
Agile
Bash
Data Modeling
Data visualization
Apache Hadoop
ETL
BigQuery
Business analysis
Database design
Data Warehouse
Business intelligence
Big Data
Containers
FastAPI
API
Databricks
Visual Basic (VB)
R
Git
Apache Airflow
Microsoft Power BI
Docker
Apache Spark
DigitalOcean
Kubernetes
Airflow
Docker Compose
CI/CD
PostgreSQL
MySQL
Dagster
Machine learning
PySpark
Data Science
MLflow
Make
Direct hire
Possible
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Experience Highlights

Software Engineer
Apr 2025 - Ongoing6 months
Project Overview

It's a task tracker used for personal needs.

Responsibilities:
  • Developed back-end functionality using a microservice architecture.
  • Built front-end components with FastHTML.
  • Implemented notifications using the ntfy.sh service.
  • Wrote unit and integration tests to ensure system reliability.
  • Integrated LLMs to generate day-at-a-glance summaries.
Project Tech stack:
Python
FastAPI
HTML
Software Engineer
Jul 2025 - Aug 20251 month
Project Overview

It's a wrapper around ntfy.sh service to foster and ease the implementation of shell notifications for any process. This package is designed explicitly for self-hosting services.

Responsibilities:
  • Developed the core code wrapper.
  • Designed system interactions and workflows.
  • Open-sourced the project code.
Project Tech stack:
Python
Bash
Lead Software Engineer
May 2024 - Feb 20259 months
Project Overview

It's an intrapreneur venture aimed at digitalizing a car dealership.

Responsibilities:
  • Developed back-end architecture using a microservices approach.
  • Built front-end interfaces to support back-office operations.
  • Integrated with instant messaging providers.
  • Integrated with credit score services, including Equifax.
  • Deployed backend services through CI/CD pipelines, maintaining 99.999% uptime.
  • Wrote unit, integration, and end-to-end tests to ensure system reliability.
Project Tech stack:
Python
FastAPI
HTML
Docker Compose
PostgreSQL
CI
CD
API
Software Engineer
Apr 2024 - Sep 20245 months
Project Overview

It's an open-source Python version of the Spicy IDs system.

Responsibilities:
  • Developed an implementation of the Spicy ID framework in Python.
  • Open-sourced the project code.
  • Wrote comprehensive tests to ensure functionality and stability.
  • Deployed the package to PyPI.
Project Tech stack:
Python
Senior Data Engineer
Sep 2023 - Jun 20249 months
Project Overview

The project aimed to improve the quality and speed of data in the company’s data lake and data warehouses for a fintech platform serving businesses.

Responsibilities:
  • Deployed the Dagster orchestrator for data workflow management.
  • Developed DAGs to automate and manage data processing tasks.
  • Integrated Dagster with DBT for data transformation and modeling.
  • Implemented process triggers to streamline pipeline execution.
  • Integrated the system with all relevant data sources and sinks.
Project Tech stack:
DBT
Dagster
Python
GCP
Senior Data Engineer
Apr 2022 - Mar 20241 year 11 months
Project Overview

It's a data lake development for a fintech platform serving businesses.

Responsibilities:
  • Built a medallion-tiered data lake on Google Cloud Storage (GCS).
  • Deployed a CDC solution using Datastream on GCP, integrating MySQL and PostgreSQL sources across multiple clouds.
  • Implemented data lake pipelines with DBT across all layers.
  • Built enriched One Big Tables to serve internal customer needs.
Project Tech stack:
Python
DBT
AWS
GCP
MySQL
Lead Data Engineer
May 2023 - Dec 20237 months
Project Overview

It's a credit scoring pipeline for a fintech platform serving businesses.

Responsibilities:
  • Developed a scoring algorithm and refactored code using clean architecture.
  • Built a pub/sub process for near-real-time and batch entity processing.
  • Wrote unit and integration tests with Pytest.
  • Deployed the solution on AWS.
Project Tech stack:
Python
AWS Lambda
AWS
Senior Data Engineer
Nov 2020 - Feb 20221 year 3 months
Project Overview

It's a data lake development and maintenance for a utilities company from Chile.

Responsibilities:
  • Created and deployed SSIS pipelines and artifacts to source data from SQL Server.
  • Built and deployed PySpark pipelines to integrate data from additional sources.
  • Developed a data lake and integrated it into a SQL Server database.
  • Designed and populated multiple data warehouses.
  • Maintained and optimized the data lake architecture.
Project Tech stack:
Microsoft SQL Server
Databricks
Python
Transact-SQL (T-SQL)
Senior Data Engineer
May 2021 - Dec 20217 months
Project Overview

It's a data lake for a utilities company to enhance its operations and facilitate cross-selling across multiple channels.

Responsibilities:
  • Developed a data lake integrating data from multiple databases and platforms.
  • Established a governed data management process based on the DAMA framework.
  • Deployed batch and near–real-time data acquisition pipelines.
  • Utilized BigQuery scheduled queries to create and maintain tables and views in a structured manner.
  • Deployed PySpark pipelines to perform large-scale data transformations.
Project Tech stack:
Python
PySpark
Databricks
BigQuery
GCP
Senior Data Engineer
Dec 2020 - Jul 20216 months
Project Overview

It's an ML containerization and deployment for a government agency to analyze its workload and enable operational efficiencies.

Responsibilities:
  • Containerized an API-based ML model using Docker.
  • Orchestrated Docker containers with Docker Compose.
  • Deployed the solution on a remote platform using Make and Bash scripts.
  • Developed and fine-tuned ML models using MLflow and Python.
Project Tech stack:
Docker
Docker Compose
Python
MLflow
Bash
Make
Senior Data Engineer
Nov 2020 - Feb 20213 months
Project Overview

The project focused on building a daily predictive model to forecast customer energy consumption for a utilities company using time series analysis.

Responsibilities:
  • Developed PySpark data pipelines to feed input to ML algorithms.
  • Built and deployed predictive models using Facebook’s Prophet framework.
  • Optimized Spark code to reduce runtime and improve performance.
  • Developed and deployed multiple ML models using MLflow.
Project Tech stack:
Databricks
Microsoft Azure
Data Modeling
Data Science
Machine learning
Python
PySpark
MLflow

Languages

Portuguese
Pre-intermediate
Spanish
Advanced
English
Advanced

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