Freelancer profile translated to English.
Back to original languageAbout Youssef
I am looking for backend challenges, whether it's an MVP or a well-established product with several microservices. My goal is to provide scalable, performant solutions with defined KPIs according to the product domain.
French
Native or bilingual
English
Fluent
Arabic
Native or bilingual
Can work on-site
Lyon (up to 50km), Paris (up to 50km), Nantes (up to 50km), Marseille (up to 50km)
Experience
- Sekoia.ioBackend engineerSOFTWARE PUBLISHINGMarch 2023 - Today (3 years and 3 months)Paris, France
- Design and development of SOL, an internal query language (DSL) translating analyst queries into SQL, ClickHouse, and Elasticsearch — enabling the creation of complex multi-engine detection rules without knowledge of the underlying systems.
- Development of a backtesting engine for Sigma rules on historical Elasticsearch data, significantly reducing the validation cycle and allowing for large-scale testing (10M+ events per community).
- Design and maintenance of asynchronous pipelines (FastAPI, Celery) for massive CRUD operations in a high-throughput environment.
- Architecture of an LLM-assisted analytical layer translating natural language questions into validated SOL queries, combining statistical inference (growth rate, anomaly detection, first-seen) and LLM reasoning in a deterministic pipeline.
- Implementation of client-side CSV ingestion for event/alert filtering, based on S3 + Parquet storage and integrated with SOL.
- Optimization of SQL and ClickHouse query performance: bottleneck identification via APM, stress tests, and plan analysis, index implementation, subquery and loading pattern optimization — significantly reducing latency.
- Development of a Kafka-based notification system for large-scale CRUD operations (real-time emails and in-app notifications).
- Debugging and incident resolution via Grafana; deploying fixes directly into Kubernetes pods.
- Improvement of asynchronous workflows through queue prioritization and reduction of overall latency.
- Implementation of multi-factor authentication and recovery codes, contributing to SOC 2 compliance.
- Maintaining test coverage >90% (Pytest, Docker) and managing production incidents.
- 7 PartnersSoftware engineerCONSULTING AND AUDITSJanuary 2009 - January 2021 (12 years)Lyon, France
- Replacement of manual Excel/VBA workflows with Python tools, eliminating volume limitations and drastically reducing processing times.
- Development and deployment of a web application on Cloud Run to automate the collection and structuring of public data, serving sales teams.
- FieldBox AIData scientistSOFTWARE PUBLISHINGJanuary 2012 - January 2019 (7 years)Bordeaux, France
- Design of ETL pipelines and modeling workflows (Airflow, FastAPI) for industrial dashboards and time-series monitoring tools.
- Implementation of anomaly detection systems on pressure time-series (Isolation Forest + statistical signals), with adaptive thresholds to reduce false positives in production.
- Transformation of raw data into supervised problems (time-series features, sliding windows, moving statistics); training of models (Random Forest, Gradient Boosting) as well as ARIMA and Prophet for forecasting.
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Education
- Generalist engineer in information processingTélécom Bretagne2019Ingénieur généraliste en traitement d'information
- Preparatory class (Grandes Écoles preparatory classes)Lycée Mohamed V2016Classe préparatoire (Classes Préparatoires aux Grandes Écoles)