Join Twilio as a Senior Software Engineer for Stytch fraud prevention team. Shape next-generation fraud detection and prevention products, primarily working on Device Fingerprinting to detect bots, manual abuse, and sophisticated reverse engineering threats. Partner with product and engineering leadership to evolve detection techniques and stay ahead of emerging threats. Operate in a high-ownership startup environment backed by Twilio's scale. Responsibilities include building fraud detection capabilities, designing and owning systems, collaborating across teams, mentoring engineers, and improving production quality through observability and incident response. Required: 6+ years designing and operating production systems, familiarity with C/C++, production experience with modern programming languages, Bachelor's in Computer Science or related experience, excellent communication skills, ability to work non-standard hours and on-call rotations. Desired: JavaScript, Go, WebAssembly experience, reverse engineering knowledge, security software engineering background. Remote role in US or Canada with occasional travel for in-person meetings. Competitive compensation, equity plan participation, healthcare, 401(k), paid time off, parental leave. Twilio is an equal opportunity employer committed to diversity and inclusion.