Python Application Developer Jobs in Ontario (NOW HIRING)

The Senior Application Security Engineer plays a critical role in driving secure software development and application security maturity within TripleLift's Engineering and Security organization, directly influencing how we protect our advertising platforms and the trust our publishers and advertisers place in us. In this position, you will partner closely with Engineering, Platform, Cloud Infrastructure, and Security teams to shape secure coding practices, application security tooling, vulnerability remediation, and CI/CD security, ensuring security is embedded into how we design, build, deploy, and operate our products.This is an exciting opportunity for someone who wants to build and scale an application security program at a company operating at the center of a rapidly evolving, high-stakes ad-tech landscape, while contributing meaningfully to the long-term security posture and resilience of the organization.

• Play a critical role in building and maintaining a global security compliance program based on NIST CSF.
• Scale application security by developing automated security testing utilizing enterprise SAST, DAST, and code-review tools.
• Champion SDLC to promote secure application development and infrastructure deployment and facilitate secure coding remediation activities.
• Automate security testing in CI/CD pipelines to detect vulnerabilities early, including building and maintaining the pipeline integrations themselves.
• Administer and drive adoption of GitHub Advanced Security (GHAS) : code scanning, secret scanning, and dependency review across engineering repositories.
• Participate in threat modeling and design/architecture spec reviews to identify and mitigate security risks early in the SDLC.
• Coordinate with stakeholders to develop and implement a vulnerability management program and to perform threat-hunting activities.
• Own and conduct internal penetration testing and vulnerability assessments of applications and infrastructure, and validate findings from third-party pentest engagements.
• Monitor and respond to application-layer security threats like API abuses, business logic flaws, and common web vulnerabilities.
• Collaborate with product and engineering teams to ensure security is a key consideration in software design and architecture.
• Enhance application security posture by working with cross-functional teams to implement proper authentication, authorization, and data protection mechanisms.
• Enhance and facilitate security incident handling activities.
• Evangelize security best practices and provide education and awareness to company employees. Develop and implement secure coding guidelines and conduct secure development training for engineers.
• Evaluate and continuously improve the maturity of the security program through the deployment and management of various security tools and processes.

• 5 years minimum of experience in application security, secure software development, security engineering, or a similar role. 
• Strong understanding of secure coding practices and ability to guide developers on remediation strategies.
• Experience with GitHub Advanced Security (GHAS), including Code Scanning (SAST), Secret Scanning, and Dependency Review.
• Proficiency in SAST, DAST, and SCA tools (e.g., CodeQL, Burp Suite, OWASP ZAP, Snyk, Checkmarx, Veracode).
• Hands-on experience integrating security testing tools into CI/CD pipelines for automated security scanning, including designing and building pipeline workflows.
• Hands-on penetration testing / offensive security experience across web applications, APIs, or cloud infrastructure.
• Knowledge of common application security vulnerabilities and mitigations (OWASP Top 10, CWE, business logic flaws, API security).
• Ability to perform threat modeling and participate in design/architecture spec reviews to assess security risks in applications and services.
• Experience conducting security code reviews across various programming languages (e.g., Python, Java, TypeScript, Go).
• Understanding of security fundamentals with relation to various cybersecurity and compliance frameworks, particularly NIST CSF, but any of PCI, SOC2, HITRUST, ISO 27001/2, or similar.
• Strong understanding of AWS security services and controls (IAM, VPC, KMS, GuardDuty, CloudTrail) and experience securing cloud-native environments and workloads, with the ability to deploy security tools within them.
• Takes ownership of projects, works independently with minimal oversight, and delivers results in a fast-paced environment while balancing multiple priorities.
• Continuously learns, adapts, and values correctness, efficiency, and constructive feedback.

Preferred:

• Experience in the ad-tech / programmatic advertising industry, or another high-scale, real-time environment.
• Preferred: Familiarity with using AI/LLM-based tools (e.g., Claude or similar) for threat intelligence, alert triage, or security automation.
• Holds a cybersecurity certification, e.g., OSCP, GWAPT, CISSP, CISA, etc.