Junior Data Scientist

Who are we? Hi! 👋 We are Ravelin! We’re a fraud detection company using advanced machine learning and network analysis technology to solve big problems. Our goal is to make online transactions safer and help our clients feel confident serving their customers. We value work/life balance, a flat hierarchy, and a culture built on empathy, ambition, unity, and integrity. Join us to learn cutting‑edge tech and work with bright, friendly people.

The Team You will be joining the Detection team. The Detection team is responsible for keeping fraud rates low and clients happy by continuously training and deploying machine learning models. We aim to make model deployments as easy and error‑free as code deployments. Google’s Best Practices for ML Engineering is our bible. Our models are trained to spot multiple types of fraud using real‑time data sources. Prediction pipelines must return results in under 300 ms. When models underperform, it’s the Detection team’s job to investigate. The team works closely with Data Engineering and Intelligence & Investigations.

The Role We are looking for a Data Scientist to help train, deploy, debug, and evaluate our fraud detection models. Our ideal candidate is pragmatic, approachable, and knowledgeable tempered by past failures. Evaluating fraud models is hard—often lacking labels for months—requiring judgment in ambiguous cases and in assessing model veracity. We build robust models that adapt to new fraud tactics and stay ahead of fraud. This role involves safe incremental progress and research, and you’ll work on both aspects of the job.

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• Build out our model evaluation and training infrastructure
  
• Develop and deploy new models to detect fraud while maintaining SLAs
  
• Write new features in our production infrastructure
  
• Research new techniques to disrupt fraudulent behaviour
  
• Investigate model performance issues (using your experience of debugging models)
  

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• Around 1 year of experience building and deploying ML models using the Python data stack (numpy, pandas, sklearn)
  
• Strong analytical skills
  
• Strong collaboration with colleagues outside your immediate team, e.g., client support or engineering
  
• Skilled at communicating complex technical ideas to a range of audiences
  
• Ability to prioritise and manage your workload
  
• Comfortable working with a hybrid team
  

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• Flexible Working Hours & Remote‑First Environment
  
• Comprehensive BUPA Health Insurance
  
• £1,000 Annual Wellness and Learning Budget
  
• Monthly Wellbeing and Learning Day (last Friday of the month)
  
• 25 Days Holiday + Bank Holidays + 1 Extra Cultural Day
  
• Mental Health Support via Spill
  
• Aviva Pension Scheme
  
• Ravelin Gives Back – monthly charitable donations and volunteer opportunities
  
• Fortnightly Randomised Team Lunches
  
• Cycle‑to‑Work Scheme
  
• BorrowMyDoggy Access
  
• Weekly Board Game Nights & Social Budget
  
• Job offers may be withdrawn if candidates do not meet pre‑employment checks