Founding Device Fingerprinting Engineer

Prelude is a company that redefines how companies authenticate and onboard users. The company is looking for a Founding Device Fingerprinting Engineer to join their team in Paris, France. The engineer will be responsible for building and hardening device fingerprinting systems, developing network intelligence signals, and applying machine learning to fingerprinting problems.

Requirements

• 5+ years of experience in a relevant field — fraud detection, bot mitigation, mobile security, or detection engineering
• Deep knowledge of device fingerprinting — mobile hardware signals, OS-level attestation (Play Integrity, DeviceCheck, SafetyNet), browser fingerprinting APIs, and spoofing/emulation detection
• Hands-on experience with network intelligence — TLS fingerprinting (JA3/JA4), IP enrichment pipelines, proxy/VPN classification, AS number analysis, and carrier-level signals
• Applied ML experience in a security context — feature engineering, anomaly detection, clustering, and classification with end-to-end ownership from training through production deployment
• An adversarial mindset — you know the attacker landscape (emulators, spoofing techniques, anti-detect browsers, residential proxy networks) and design systems with bypass attempts already in mind
• A preference for simple, robust designs over clever, fragile ones — with strong intuition for what will hold up at scale under active adversarial pressure

Benefits

• Competitive salary
• Stock options
• Flexible working hours
• Professional development opportunities