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Nil Andreu Gordillo

@nilandreugordillo

Senior Machine Learning Engineer at Lingokids who improved recommendation engagement and week-1 retention with a LightGBM ranking model.

Spain

Message

At Lingokids, I built a LightGBM LambdaRank recommendation model that increased recommended activities played by 29%, playtime by 3%, and week-1 retention by 1.4% in A/B tests. I extended the ranking framework to unsubscribed users, with estimated annual net revenue impact growing from approximately $200k to $1.5M+.

I also designed the daily model-serving pipeline with MLflow and Spark, and led the extraction of the dbt repository into an independent project. At Veepee, I delivered Product Personalization for Clearance Sales from POC to production, and developed a Scala gRPC serving layer for 30+ models.

Earlier, at Back Market, I created an Airflow and SQL workflow that reconciled 99.8% of marketplace financial flows. At Outfund, I created a recommendation system for 100k+ leads that increased conversion by 10%; at Veepee, I developed an image-classification algorithm that improved class coverage by 20% and accuracy by 15%.

Experience

Work history, roles, and key accomplishments

Current

Senior Machine Learning Engineer

Current

Lingokids

Nov 2025 - Present (11 months)

Built a LightGBM LambdaRank recommendation model for subscribed users, achieving +29% recommended activities played, +3% playtime, and +1.4% week-1 retention in A/B tests. Extended the ranking framework to unsubscribed users and designed the daily model-serving pipeline using MLflow and Spark UDFs.

Python LightGBM MLFlow Spark DBT Databricks Recommendation Systems A B Testing Model Serving Data Pipelines

Machine Learning Engineer II

Veepee

Jul 2024 - Nov 2025 (1 year 4 months)

Designed and deployed new recommendation model features, boosting Conversion Rate by +2.1% in A/B tests and generating an estimated €1M+ incremental annual revenue. Delivered Product Personalization for Clearance Sales from POC to production, achieving +14.67% Add-to-Cart and +14.86% Conversion Rate across 9 sales events.

TensorFlow Keras Scala Java DBT Airflow MLFlow Dataflow BigQuery gRPC Onnx LightGBM Recommendation Systems A B Testing Model Serving

Experienced Backend Engineer

Back Market

Apr 2023 - Jul 2024 (1 year 3 months)

Implemented the shift of seller payouts from a 10-day cycle to a 7-day cycle. Created a workflow with Apache Airflow and SQL reconciling 99.8% (2 billion €) of financial flows in marketplace.

Django Flask Airflow RabbitMQ SQL Kubernetes Financial Reconciliations Workflow Automation

Machine Learning Engineer

Outfund

May 2022 - Apr 2023 (11 months)

Built on-demand revenue forecasting models and created a Recommendation System for +100k leads which increased conversion rate by +10%. Developed in dbt an Anomaly Detection System on 15 financial metrics for a portfolio of +800 companies.

fastAPI scikit learn XGBoost Pandas Kafka DBT Snowflake Anomaly Detection Recommendation Systems Data Pipelines

Data Scientist

Veepee

Dec 2021 - May 2022 (5 months)

Extracted +2M images with +15 features and stored backups in S3. Created a multi-classification deep learning algorithm for image classification on 12 label groups with up to 550 class labels, improving the State-Of-Art algorithm by +20% on class coverage and increasing accuracy +15%.