Sr Application Security Engineer

About the role

The Trade Desk is seeking a Senior Application Security Engineer to join our Cybersecurity Department. This role will complement and expand our existing application security capabilities, offering significant opportunities to make a substantial impact.

Responsibilities

• Extend and own scalable AppSec tooling across four core areas: SAST/DAST pipeline integration, vulnerability management, threat modeling frameworks, and security posture.
• Validate findings end-to-end: triage and reproduce scanner output to separate signal from noise, then contextualize risk so engineering teams understand exactly what to fix, why it matters, and what the customer impact would be if exploited.
• Review and assess new features, APIs, and architectural changes; conduct security-focused code reviews (C#, Java, JavaScript, or similar) and application-layer penetration tests.
• Write production-quality security automation and tooling — this role ships code alongside security guidance.
• Assess and help secure AI/ML systems — including inference APIs, LLM integrations, and GenAI attack surfaces such as prompt injection and model exfiltration — and build AI-augmented tooling to scale the team's output.
• Drive security culture through direct engineering partnership: advising on secure-by-design patterns early in the development process, raising the security floor across hundreds of engineers, and keeping customer trust at the center of every recommendation.
• Participate in and drive security governance-first frameworks to include developing and publishing standards, guidelines, procedures, secure baselines, and policies.

Requirements

• BS degree or equivalent years of experience in related field
• 6-8+ years in application security with a track record of building tooling and automation, not just operating it
• Active software development experience — you write clean, production-ready code in at least one of: C#, Java, Python, Go, or JavaScript
• Certifications such as OSWE, GWAPT, CSSLP, OSCP, or cloud security certifications (AWS, GCP, or Azure)
• Experience in ad tech, large-scale SaaS, or other high-throughput consumer or enterprise platforms is a plus

Qualifications

• Hands-on experience with SAST, DAST, SCA, and secrets management tooling, including configuration, tuning, and CI/CD integration (GitHub Actions, GitLab, Jenkins, ArgoCD, or similar)
• Practical threat modeling experience (STRIDE, PASTA, or equivalent) — producing engineering-useful outputs, not just risk documentation
• Experience with vulnerability management workflows: aggregation, triage, risk-based prioritization, and driving remediation at scale
• Working knowledge of Kubernetes and container security (Docker, Helm, Istio) and cloud security fundamentals across at least one major platform (AWS, GCP, or Azure)
• Experience in AI/ML security — securing AI pipelines, assessing LLM integrations, understanding GenAI attack surfaces, or building AI-assisted security tooling

Skills

• Strong written and verbal communication skills — able to translate technical risk into terms that resonate with engineering teams, product leadership, and the broader customer-first mindset that drives decisions at The Trade Desk

Benefits

• Comprehensive healthcare (medical, dental, and vision) with premiums paid in full for employees and dependents
• Retirement benefits such as a 401k plan and company match
• Short and long-term disability coverage
• Basic life insurance
• Well-being benefits
• Reimbursement for certain tuition expenses
• Parenthood leave
• Vacation time for full-time employees up to 120 hours thru the first year and 160 hours thereafter
• Around 13 paid holidays per year
• Competitive benefits package