Senior Software Engineer (Fraud)

Join Replit, a leading AI-native platform, as a Senior Software Engineer on the Fraud team. In this role, you will be at the forefront of defending the platform from exploitation, detecting and shutting down phishing deployments, preventing cryptomining, and stopping LLM token farming. You will work on unique problems related to AI-generated code and use LLMs as a defensive tool against abuse. This is an opportunity to gain hands-on experience applying AI to security problems in a production environment with real attackers.

• Concevoir et mettre en œuvre des garde-fous pour les LLM qui détectent les scénarios d'abus dans le code généré par l'IA et les interactions des agents.
• Construire des systèmes de détection alimentés par l'IA qui utilisent les LLM pour identifier les modèles malveillants, classifier les menaces et automatiser les décisions de réponse.
• Posséder l'ensemble du cycle de vie de la réponse aux abus : détection, enquête, application et traitement des appels en collaboration avec le support et le juridique.
• 4+ years of experience in security engineering, anti-abuse, trust & safety, or fraud detection
• Familiarity with common attack patterns: phishing infrastructure, account takeover, credential stuffing, resource abuse
• Clear communication skills for working across Security, Support, Legal, and Engineering teams
• Experience building or fine-tuning ML/LLM-based classifiers for security or abuse detection
• Familiarity with prompt injection, jailbreaking, and other LLM-specific attack vectors
• Ability to investigate complex abuse patterns and translate findings into automated defenses
• Strong programming skills in Python and/or TypeScript for building detection systems and automation
• Experience with SQL and data analysis at scale (BigQuery, Snowflake, or similar)
• Background in fraud detection, payment abuse, or financial crime
• Familiarity with device fingerprinting, IP reputation, and email validation services
• Knowledge of container security, Linux internals, or cloud infrastructure (GCP preferred)
• Experience at a platform company dealing with user-generated content or compute abuse (hosting providers, cloud platforms, developer tools)
• Experience with CI/CD security tooling (SAST, SCA, Dependabot, Snyk)
• Prior work with abuse reporting pipelines, trust & safety tooling, or content moderation systems
• We encourage people from all kinds of backgrounds to apply, including and especially candidates from underrepresented and non-traditional backgrounds