stefi

- Built from scratch the best industry labelled datasets related with Sybils attacks in crypto, which became foundational for the development of our scoring products. - Co-created the white glove data service offering that helped drive $1M in revenue in 2024. - Improved our ensemble fraud detection model performance from 0.95 to 0.99 AUC, achieving an increasing in recall for our target class by 7%. - Deployed ML algorithms detecting sybil behavioral patterns, scoring 250K+ users monthly. Reduced core app fraud rate from >30% to <15% across 2M+ users. - Developed Python automated pipelines using blockchain API’s including Alchemy, Dune, Etherscan, and other block explorers to monitor partners and competitors fraud rate and performances. - Implemented internal dashboards using Superset, AWS Glue, and Redshift to monitor KPIs and model performances.

- Reduced chargeback rate by 75% (from 2% to 0.5%) through fraud pattern identification using SQL and Python data analysis. - Produced ad-hoc data analysis, investigations and business reports for the fraud and payments business unit. - Developed, maintained and documented data infrastructure and dashboard to monitor the business unit KPI, using BigQuery and Tableau. - Using text pre-processing cleaning techniques, vectorizations and cosine similarity, developed text comparison models to detect fraud between vendors and buyers on the platform with accuracy of 85%

- Core member of 6-person strategic team driving open-source web3 community initiatives. - Designed technical onboarding protocols for data scientists transitioning to web3 environments. - Built ETL pipelines transforming blockchain data for non-technical data scientists. Led technical workshops and judged 3 hackathons on Sybil attack prevention.

- Using time series decomposition predicted national sales forecasts for 52 stores. - Developed reports on market trends and competitive positioning. - Managed full product purchasing for the cycling accessories business unit. - - Optimized pricing and product offering based on sales correlation and brand strategy. - Ranked top 3 nationally for best shortage rate and lead time optimization.