Data & AI Scientist – Fraud

About Klar We're turning one of the world's largest underbanked markets into something fairer, simpler, and more transparent.  7 million users served since 2019. Uber's first global credit card, built right here in Mexico. Klar Empresarial, a brand-new B2B solution bringing agile credit and smart accounts to SMEs who've been ignored by traditional banks for too long. And a full banking license on the horizon, because our customers asked for it and we listened. We move fast, we think big, and we go all in, because as our CEO puts it: "Growing doesn't always mean going further. Sometimes it means going deeper."  Behind all of it is a team of 30+ nationalities, working across Mexico City, Berlin, and Argentina, obsessed with building financial products that are simpler, faster, and fairer than anything that came before. This is Klar, and we're seeking the people who'll write the next chapter. Our people If you join us at Klar, you’ll be welcomed to a team that is rich in many talents and we are very proud! With our head office in Mexico City, and remote tech hubs in Berlin and Argentina, we are always learning something new about another culture or language. With so many people from different backgrounds and walks of life (young professionals, parents, LGBTQ+, neurodivergence), you’ll definitely find your people here!  and walks of life (young professionals, parents, LGBTQ+, neurodivergence), you’ll definitely find your people here!  Our values - Ownership - We own our successes & our failures as a team. - Excellence - We do everything to the best of our ability & always seek to achieve a new level of excellence in our work. - Inclusion - We believe we are stronger together and actively work to promote a safe, diverse, inclusive, and respectful culture. - Customer Obsession - We understand the value Klar can bring to its customers & it’s always at the forefront of our decisions. - Klarity - We communicate clearly & with authenticity. It’s in our name & it’s what we do. The position and your daily adventures This is a full-time position based in our Mexico City office with a hybrid model, therefore we are looking forward to seeing you in our office 2–3 times per week. We are looking for a Data & AI Scientist to join our Fraud team and help ensure that our customers use Klar's services in a reliable and secure manner. This is an ideal opportunity for someone who wants to grow at the intersection of data, generative AI, analytics, and operations. What you can expect: - Design and propose fraud models and rules end to end. This covers framing the problem, building features, training and validating models, setting thresholds, and monitoring the performance of the solutions. - Detect and size new fraud patterns before they scale, and communicate their impact clearly. - Measure with statistical rigor and understand how each change affects fraud risk and the customer experience. - Build LLM pipelines that turn unstructured text and documents into validated information for our models and monitoring. - Automate workflows with AI agents, including validation, monitoring, prompt engineering, RAG systems, and A/B experimentation. Nice to have: - Graph analysis or experience in anomaly detection. - Experience with tools such as dbt or a data orchestrator (Airflow, Dagster, Mage, or similar), and AWS. - Building tools for AI agents, such as MCP servers, skills, etc What we are looking for: - Bachelor's degree in a quantitative field (Data Science, Mathematics, Actuarial Science, Physics, Engineering, Economics, or related fields). - At least 2 years of hands-on experience in data science, automation, AI, operations, or related fields. - Advanced Python and SQL for data processing. - Experience training ML models, for example logistic regression, random forests, gradient boosting (XGBoost, LightGBM, or CatBoost), Isolation Forest, clustering, etc. - Applied statistics to measure impact: experiment design and A/B testing, hypothesis testing, confidence intervals, resampling techniques. Ability to explain the randomness in results. - Hands-on experience with LLM-based agents (structured outputs, function calling, agentic loops). - Use of AI coding agents (Claude Code, Cursor, Codex, or similar). - Use of development tools such as Git, linters, etc. - Use of REST APIs. - Clear written communication in Spanish and English, including for non-technical audiences. - Analytical thinking to identify patterns and turn observations into recommendations. Our offer to you: - Competitive salary based on performance and experience - Chance of earning Klar stock options - 15 days of paid vacation per year; plus extended maternity and paternity leaves - Vacation premium - 30 days of Christmas bonus - Food vouchers - Medical Insurance - Computer device - Wellhub  subscription to offer mental and physical health - Sponsored coaching and therapy sessions via a Mental Health Platform - A modern centrally located office in Mexico City with free drinks, snacks, and regular social events - International work environment with amazing and highly skilled people - A world class team that helps you evolve your skills in areas you're interested in Klar is a safe place for everyone! We trust our highly skilled and diverse team and we’re committed to creating a welcoming and inclusive environment for new talents to flourish. We value diversity and welcome all applications regardless of gender, nationality, ethnic and social origin, religion/belief, physical abilities, age, sexual orientation and identity. Should you require any accommodations through the recruitment process, please don’t hesitate to let us know how we can help!