Mallorca, Spain

Alexandre Coll

ETL / Data Engineer

6+ years building data pipelines and IoT platforms at scale: millions of records per day and 15K+ devices.

Work experience

ETL / Data Engineer
Wireless DNA (WDNA)
Jun 2020 – present
- Integrate sources into a ClickHouse analytical store (millions of records/day).
- Build an IoT alarm system with anomaly detection for 15K+ devices (MQTT, Pub/Sub).
- Develop an LSTM model to forecast mobile network saturation.
- Build ETL pipelines with Python, SQL, PySpark, Airflow and RabbitMQ.
- Develop REST APIs with FastAPI: internal services, alarms and a public API.
- Ensure data quality: validate, clean and correct IoT and meteorological data.
- Design PostgreSQL databases and tune them for performance.
- Deploy with Docker and CI/CD on own servers; help develop them (GitFlow).
Freelance Data Engineer
Sociedad Española de Psiquiatría y Salud Mental
Mar 2025 – Mar 2026
- Developed a Python ETL backend to extract, transform and store psychology data.
- Built a Windows app to display the data as the client required.

Personal open-source project: an open-data pipeline for Mallorca.

Ingestion and processing with Python, PySpark and Airflow on PostgreSQL.
Layered dbt project with incremental models, snapshots, docs and Grafana on top.
Data quality: 30+ dbt data tests, unit tests, source freshness and run monitoring.
Read-only REST API (FastAPI) on the gold layer, all running on a Docker Compose stack.

PythonPySparkAirflowMinIO (S3)Delta LakePostgreSQLdbtGrafanaFastAPIDocker Compose

Simplified data flow: from open data sources to dashboards and the API.

Each decision records the context, what was decided, the alternatives ruled out and its cost. Some of them (written in Spanish):

Also:dbt (personal projects)PyTorch: CNN, RNN/LSTM and GANS3-compatible OCI storageCI/CDGitFlowAWS / Azure (basic)

UIB · 2019
Bachelor's Degree in Industrial and Automatic Engineering
UIB · 2023
Master's Degree in Intelligent Systems (AI & Mobile Robotics)
Astronomer · 2026
Astronomer Certification: DAG Authoring for Apache Airflow 3
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