alexandre.coll
es

Mallorca, Spain

Alexandre Coll

ETL / Data Engineer

6+ years building data pipelines and IoT platforms at scale: millions of records per day and 18K+ devices.

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Photo of Alexandre Coll
years building pipelines
6+
years building pipelines
records per day
1M+
records per day
IoT devices
18K+
IoT devices
01

Work experience

  1. ETL / Data Engineer

    Wireless DNA (WDNA)

    Jun 2020 – present

    • Design and build a big data architecture with Hadoop (HDFS) as storage and Spark as the query engine.
    • Build an IoT alarm system with anomaly detection for 18K+ 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 public APIs.
    • 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).

  2. 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.
02

Projects

MallorcaDataPlatform

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

View on GitHub
  • Ingestion and processing with Python, PySpark and Airflow on PostgreSQL.
  • Layered dbt project with incremental models.
  • Read-only REST API (FastAPI) on the gold layer, all running on a Docker Compose stack.
PythonPySparkAirflowMinIO (S3)Delta LakePostgreSQLdbtGrafanaFastAPIDocker Compose

Architecture

  1. Open data
  2. Airflow
  3. Bronze · MinIO
  4. PySpark
  5. Silver · Delta
  6. Gold · dbt
  7. Grafana / API
Simplified data flow: from open data sources to dashboards and the API.

Architecture decisions (ADR)

See all 18 ADRs

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

03

Technical knowledge

Also:dbt (personal projects)PyTorch: CNN, RNN/LSTM and GANS3-compatible OCI storageCI/CDGitFlowAWS / Azure (basic)
04

Education & certifications

05

About me

I'm an ETL Engineer with 6+ years building data pipelines and IoT platforms at scale, handling millions of records per day and 18K+ devices.

I have experience in machine learning, anomaly detection and time-series forecasting, and I'm Astronomer-certified in Apache Airflow 3.

My goal is to keep growing in data engineering, with a particular interest in data architecture.

Languages

  • Spanish: native
  • Catalan: native
  • English: B2 (certified by the University of the Balearic Islands)
06

Contact

Let's talk. Reach me by email or LinkedIn.

alex.coll.molina@gmail.com
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