Senior Machine Learning Engineer I // II

At Signifyd , we help merchants confidently grow their businesses by building trusted relationships with their customers. Our advanced technology, combined with a team genuinely invested in our clients’ success, creates frictionless shopping experiences, approving more good orders, protecting revenue, and keeping customers happy. Trusted by thousands of leading merchants across more than 100 countries, we securely process billions of transactions each year. Our people are the heart of everything we do, driving our mission forward with commitment, empathy, and creativity. Join us on our mission to empower confident, fraud-free commerce by helping online retailers provide superior customer experiences and eliminate fraud. Learn about our company values here ! The Senior Machine Learning Engineer will join our ML team. This team is responsible for building, maintaining, and monitoring the production ML models and offline experimentation frameworks that are at the core of Signifyd’s product. This includes the core fraud detection model that decides the majority of our traffic, alongside our model training and evaluation infrastructure. We work closely with Platform Engineering teams to contribute novel modeling methods, advanced feature engineering, and robust statistical practices. Our Culture We value tenacity, curiosity, and a hunger for learning. Our adversaries are highly motivated fraudsters looking to exploit any gap. We seek equally motivated individuals who are passionate about keeping our customers safe while pulling the field of adversarial machine learning forward. The Role As a Senior Machine Learning Engineer , you will be a driver of technical execution within the ML team. You won’t just build models—you’ll own the end-to-end lifecycle of high-impact ML projects, from offline experimentation to deployment to production. You will be responsible for improving model performance, refining our experimentation processes, and ensuring our fraud detection systems are robust, scalable, and scientifically sound. Responsibilities: • Expand ML Capabilities – Identify, prototype, and integrate new ML technologies and infrastructure to enhance fraud detection effectiveness and scalability. • Enable High-Velocity Experimentation – Own the design and implementation of ML pipeline components that accelerate our innovation • Collaborate Across Functions – Partner with Product, Engineering, and Risk teams to translate business requirements into technical solutions and ensure ML initiatives align with customer needs. • Raise the Bar – Foster a culture of technical excellence by championing best practices in testing, documentation, model monitoring, and development. Requirements: • Education: A degree in Computer Science, Statistics, or a comparable quantitative field. • Experience: 4-6+ years of post-undergrad work experience in a production-grade ML environment. • Technical Depth: Strong foundation in machine learning theory, statistical evaluation, and experience with supervised/unsupervised learning at scale. • Execution Focus: Proven track record of taking ML projects from research/prototype to high-scale production environments. • Communication: Ability to communicate technical findings clearly to both technical peers and non-technical stakeholders. • Tech Stack: Proficiency in Python , SQL, key ML libraries, and Spark • Mindset: A strong outcome-oriented mindset—you care about the "why" behind the models and the business impact they create. • Attention to detail is critical in fraud prevention. To demonstrate this, please start your response to the first application question with the word 'Stochastic' Nice to have: • Previous experience in fraud, fintech, payments, or e-commerce. • Passion for writing well-test