JA.

Senior Data Engineer · Guatemala

Jeferson Stiv Argueta Hernández

I design cloud data platforms that don't page anyone at 3 AM — ELT on Snowflake with dbt, event-driven lakes on AWS and GCP, and the orchestration glue that keeps it honest. 7+ years across entertainment and media research, supply chain, marketing, telecom, pharma, and healthcare.

CV (PDF) ↗ GitHub ↗ LinkedIn ↗

Guatemala · +(502) 3312-6786 · ajefersonstiv@gmail.com

About

Senior Data Engineer with 7+ years across entertainment and media research, supply chain, marketing, telecommunications, pharmaceutical, and healthcare. Currently operating a Snowflake, dbt, and Dagster platform on GCP (GKE) with ~1,600 dbt models and ~290 Dagster assets: platform upgrades and security fixes, pipeline stabilization, data observability, and release management.

Skilled in relational and NoSQL databases, Python, C#, Julia, JavaScript, C++, and Linux servers. IT graduate from Universidad Mariano Gálvez, with a Master’s Degree in Information Security (2026).

I care about clean data models, observable pipelines, and small improvements that compound — the kind of engineering that survives audits, cloud-bill reviews, and 2 AM on-call pages.

Experience

Senior Data Engineer

TeamInternational · Medellín, Colombia · — Present

  • Designed and maintained ETL and ELT pipelines in Postgres and Snowflake using dbt, Snowpark, and PySpark; introduced custom macros and incremental strategies to automate DDL/DML and Slowly Changing Dimension (SCD) loads.
  • Built large-scale ingestion and transformation pipelines in Python/Spark; tuned Snowflake warehouses and queries to improve performance and reduce compute spend by 35%.
  • Implemented an event-driven data lake on AWS and GCP and exposed curated datasets via FastAPI endpoints to power dashboards and downstream applications.
  • Developed robust SQL for data quality and cleaning, with automated checks and retries for resiliency.
  • Partnered with Data Science / ML teams in a Scrum setting to productionize features and datasets; contributed to sprint planning and estimations, and communicated roadmaps and results to stakeholders.

Big Data Engineer

Millicom (Tigo) · Guatemala · —

  • Migrated the on-premises data warehouse to AWS, rewriting Talend pipelines in Python/PySpark and adopting S3, Glue, Lambda, Athena, Redshift, ECS/Fargate; improved pipeline execution times by 40–50% and simplified operations with containerized runs.
  • Built data-lake pipelines on S3 with PySpark and Python; automated orchestration with Airflow.
  • Integrated Kafka and Kinesis for streaming to enable near real-time analytics and alerts.
  • Performed data modeling and data mining on large-volume datasets to support analytics use cases.
  • Collaborated with DS/ML and business stakeholders in network analytics within a Scrum team.

Data Analyst / Business Intelligence

IQVIA · Guatemala · —

  • Built batch and incremental pipelines with Python and SSIS to integrate healthcare/pharma sources into a SQL Server data warehouse; implemented SCD patterns and audit logging to ensure lineage and traceability.
  • Designed star/snowflake dimensional models and wrote production-grade T-SQL (CTEs, window functions, stored procedures) to curate KPIs and subject-area data marts for commercial and medical stakeholders.
  • Automated reporting with SSRS, Tableau, and Power BI, streamlining recurring deliverables and standardizing refresh schedules.
  • Led KPI standardization and report-delivery improvements; refactored critical T-SQL stored procedures used for data quality and processing/cleaning, improving runtime by 70% and stabilizing refreshes.
  • Established data-quality checks and alerting to improve reliability of downstream dashboards and analyses.

Software Engineering National Consultant

CDAG · Guatemala · —

  • Developed an internal process-management web application on .NET Framework, increasing stakeholder visibility into process status by 40%.
  • Automated data cleaning and reporting with Python and C#; delivered BI with SSRS and Power BI.

Selected Projects

Operating and hardening a Snowflake / dbt / Dagster platform on GKE

For a two-repo data platform (~1,600 dbt models, ~27K tests, ~290 Dagster assets), led the Dagster, dbt-core, and Python major upgrades, closing 8 CVEs and removing an SQL-injection path from a custom Snowflake IO manager. Fixed recurring out-of-memory failures by reusing the dbt partial-parse artifact across Dagster runs; built source freshness checks and model-health signals for a client-facing status view, and automated the hand-off from the weekly pipeline run to the client’s QA suite with failure alerts.

  • Snowflake
  • dbt
  • Dagster
  • GKE
  • Security
  • Observability

Cloud migration: AWS → GCP

Migrated a serverless-first data platform from AWS to GCP, replicating the architecture with Python, PySpark, Dagster, Snowflake, and dbt. On AWS, workloads ran on ECS Fargate with S3 as the data lake; re-platformed to GCP managed services while preserving data models, orchestration patterns, and SLAs. Validated end-to-end with data-quality checks; reduced cloud spend by 45% and, after optimizations identified during re-platforming, improved pipeline execution times by 35%.

  • GCP
  • AWS
  • Dagster
  • Snowflake
  • dbt
  • PySpark

LLM agent for aircraft-repair knowledge

Built a retrieval-augmented agent on GCP to surface historical maintenance insights from Oracle records. Dual-pipeline architecture: Python on Compute Engine (cron) extracted from Oracle to Cloud Storage; Cloud Functions → Airflow DAG loaded curated layers into Postgres following a medallion architecture (bronze / silver / gold). Indexed entities and documents for embeddings in Postgres and served them through a Vertex AI LLM agent for search and Q&A across past repair procedures — end users resolve maintenance issues 60% faster by leveraging historical repair context.

  • Vertex AI
  • RAG
  • GCP
  • Airflow
  • Postgres
  • Medallion

Technical Skills

Cloud & Warehousing

  • AWS (S3, Lambda, Glue, ECS/Fargate, EC2, Athena, Aurora, SNS/SQS)
  • GCP (Cloud Storage, GKE, Pub/Sub)
  • Snowflake
  • Redshift
  • Oracle
  • Postgres
  • DB2
  • MySQL
  • SQL Server
  • MongoDB
  • Apache Cassandra
  • Hadoop
  • DuckDB

Orchestration & Modeling

  • dbt (incremental models, macros, tests)
  • Dagster (assets, partitions, sensors)
  • Airflow
  • Star / Snowflake
  • SCD
  • Change Data Capture

Processing & Pipelines

  • PySpark
  • Snowpark
  • SQL
  • ELT / ETL design
  • Event-driven / serverless

Streaming & Integrations

  • Kafka
  • Kinesis
  • FastAPI
  • REST

BI & Reporting

  • Tableau
  • Power BI
  • SSIS
  • SSRS
  • Crystal Reports

Programming & Tools

  • Python
  • SQL
  • C#
  • JavaScript
  • C++
  • Julia
  • Docker
  • Kubernetes (GKE)
  • Git
  • GitHub Actions CI/CD
  • Claude Code
  • Linux servers
  • Agile / Scrum

Data Quality & Governance

  • dbt tests
  • Source freshness checks
  • Data observability
  • Lineage
  • Audit logging
  • RBAC

Training & Certifications

From GitHub

Pinned and most recent public repositories, loaded live from the GitHub API.

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