Senior AppSec Engineer — End-to-End Security & AI Tooling

Relay; Toronto; On-site; CAD 180,000 - 220,000; Full time

Job summary

Relay is seeking an Senior Application Security Engineer II to own a defined slice of our platform end-to-end, testing services, identifying exploitable gaps, and fixing issues alongside our senior engineers who maintain the auth system and build DAST tooling. You will threat model designs, run white-box tests, triage bug reports, and coordinate fixes with owners, writing patches when appropriate.

You’ll use Datadog security, Burp Suite, and in-house tools, while leveraging AI tooling like

Qualifications

• 5 to 6 years of professional security experience.
• Shipped production code with security in mind.
• Deep understanding of OWASP Top 10 and mitigations.
• Experience with AI tooling in daily work.
• Clear communicator and collaborator with developers.
• Ownership and mentorship mindset.
• Familiar with security testing in cloud environments.

Responsibilities

• Threat model technical designs and run white-box tests.
• Triage bug bounty reports and coordinate fixes with owners.
• Contribute patches to Relay’s codebase when appropriate.
• Work with Datadog security, secrets scanning, Burp Suite, and in-house tools.
• Build with AI as a default using Claude Code and Cursor.

Skills

Threat modeling

Penetration testing

Product security engineering

AI tooling in security

Communication

Mentorship

Ownership

Tools

Burp Suite

Datadog

CI/CD tooling

Job description

Relay is seeking an Senior Application Security Engineer II to own a defined slice of our platform end-to-end, testing services, identifying exploitable gaps, and fixing issues alongside our senior engineers who maintain the auth system and build DAST tooling. You will threat model designs, run white-box tests, triage bug reports, and coordinate fixes with owners, writing patches when appropriate.

You’ll use Datadog security, Burp Suite, and in-house tools, while leveraging AI tooling like