You're seeing this page as if you were . The main menu is still yours, though. Exit from immersion
Tiago GimenezTG

Tiago Gimenez

DATA SCIENTIST

€200/day
Paris, FR
8-15 years

Average response time: 1 hour

About Tiago

I’m a highly skilled Data Scientist with a solid background in fraud prevention, driven by a passion for solving complex challenges and safeguarding financial ecosystems. I hold a Bachelor’s degree in Statistics from the University of Campinas, one of the top universities in Latin America, and over 6 years of hands-on experience in the payment and financial sectors.

💡 What I do best:

- Building and improving fraud prevention systems: From designing fully automated systems that prevent card fraud attacks to crafting realtime decision models. I’ve been at the forefront of protecting businesses from fraudulent activities.
- Driving accuracy and impact: With achievements like maintaining a 99%+ true positive rate in rule application and a 98% recall in fraud detection systems, I focus on actionable results.
- Strategic antifraud design: I contributed to developing secure and scalable fraud prevention strategies for emerging banking products.

🔍 Key achievements I’m proud of:

- Developed realtime antifraud transaction decision rules with over 99% assertiveness, effectively minimizing fraud impacts while ensuring no friction for legitimate transactions.
- Built an identity theft detection system with zero false positives at Stone, leading to the automatic removal of 4000+ fraudulent accounts in just two months.
- Investigated social engineering fraud schemes and prevented account takeover cashout operations at Stone, getting expertise in cybersecurity and information security.
- Reduced error rates in fraud detection by 50% at Cielo, leveraging data driven rules that significantly lowered chargeback rates.

🛠️ Technical toolkit:

- Programming Languages: Python, SQL and R.
- Machine Learning Models: Regressions, tree-based models and neural networks.
- Other Skills: Statistical analysis, data exploration, data mining, predictive modeling, etc.

💻 Github: github.com/tiagogimenez
linkedin.com/in/gimeneztiago
  • English

    Native or bilingual

  • Portuguese

    Native or bilingual

  • Italian

    Fluent

  • French

    Conversational

Can work on-site
Paris (up to 50km)

Experience

  • Stone Co.
    DATA SCIENTIST
    BANKING AND INSURANCE
    January 2022 - May 2025 (3 years and 4 months)
    • Managed and implemented rules at the initial stage of transaction flows for PSP and gateway transactions, achieving a 99%+ true positive rate in rule application.
    • Designed, developed, and maintained a fully automated system for preventing card fraud attacks, incorporating real-time actions such as API key blocks and client vulnerability notifications. Achieved 98% assertiveness and recall, effectively mitigating fraud risks.
    • Created an identity theft account detection system with zero false positives, leading to the automatic deletion of 4000+ fraudulent accounts within two months with 100% assertiveness.
    • Trained and improved machine learning models to detect and decline fraud in real-time decisions for e-commerce transactions.
    • Contributed to designing the anti-fraud strategy for Stone Bank's card products, ensuring secure and scalable growth for this new product.
    • Defined and implemented banking anti-fraud rules based on in-depth data analysis to decline fraudulent transactions in real-time payment flows.
    • Designed official dashboards to monitor the performance of real-time antifraud rules across the transaction payment flow.
    • Conducted cybersecurity field investigations, identifying social engineering frauds on the internet and preventing cashout operations in account takeover scenarios.
  • Banco PAN (Brazilian digital bank)
    FRAUD PREVENTION ANALYST
    BANKING AND INSURANCE
    July 2021 - December 2021 (5 months)
    • Successfully identified purchased accounts - those that are genuine but created solely for fraudulent purpose. Implemented rules that prevented such accounts from being opened, leading to a 60% reduction in the occurrence of purchased accounts.
  • Cielo (Brazilian acquirer)
    FRAUD PREVENTION ANALYST
    BANKING AND INSURANCE
    November 2019 - June 2021 (1 year and 7 months)
    • Pioneered the creation of data-driven rules for combating fraud in real-time decision making. Through data analysis, these rules reduced the error rate from 6% to 3% and decreased the chargeback rate since their implementation.
    • Identified and implemented real-time fraud prevention rules for high chargeback clients.
    • Developed a makeshift data analysis workflow using R and decision tree models.

Recommendations

Be the first to recommend Tiago

Help this freelancer shine by sharing your experience working together.

These freelancer profiles also match your criteria

AgathaA

Agatha Frydrych

Backend Java Software Engineer

4.7

(3)

2

BaptisteB

Baptiste Duhen

Fullstack developer

4.6

(4)

5

AmedA

Amed Hamou

Senior Lead Developer

4

(2)

7

AudreyA

Audrey Champion

Web developer

4.3

(3)

4

Education

  • BACHELOR IN STATISTICS
    University of Campinas
    2020
    BACHELOR IN STATISTICS

Skill set

Categories