Senior Application Security Engineer

MoonPay•Canada - Remote, NY

2d•Remote

About The Position

Our SRE/Cloud Security teams are a dynamic blend of proactive defenders and inquisitive problem-solvers. We are dedicated to strengthening our systems through rigorous security reviews and hands-on penetration testing, and we actively manage our Bug Bounty program to ensure timely validation, response, and remediation. We leverage cutting-edge tools and techniques to build robust defenses, and collaboration is central to how we work; embedding security best practices throughout the SDLC. We continuously research emerging threats, develop effective mitigation strategies, and empower engineering teams through clear guidance and practical security training. We maintain up-to-date security standards and documentation, lead incident response efforts with precision, and are passionate about spreading a secure-by-design culture while contributing to the wider security community.

Requirements

Developed a breadth of experience across multiple security domains, including web and mobile application security, infrastructure and cloud security, and can connect these areas to drive a holistic security approach.
Hands-on experience performing white-box, source code-assisted web and mobile application penetration testing, from vulnerability discovery through triage and exploitation.
Ability to read, understand, and review source code to identify security issues, with ideally, a particular focus on JavaScript and TypeScript codebases.
Strong understanding of Threat Modelling principles and their practical application to the secure software development lifecycle (SDLC).
Experience working with web application firewalls to help protect applications, assess coverage, and support tuning rules to mitigate common attack patterns.
Experience embedding application security practices into CI/CD pipelines, enabling early detection of vulnerabilities and close collaboration with engineering teams throughout the development lifecycle.
Collaborated closely with engineering teams to clearly communicate security findings, explain vulnerabilities, attack paths, and mitigations, and support the implementation of effective fixes for both technical and non-technical audiences.
Self-motivated, proactive, and take strong ownership of your work, operating effectively in a remote environment while maintaining a collaborative, team-focused mindset.

Nice To Haves

Experience in JavaScript and TypeScript, including the ability to read, understand, and reason about modern web application codebases.
Experience working with Cloudflare, including its hosting and Web Application Firewall (WAF) capabilities, to help secure and operate internet-facing applications.
Experience testing and securing GraphQL, REST APIs, including understanding common GraphQL/REST-specific attack vectors and security considerations.
Experience or a strong interest in Web3 security testing, including assessing smart contracts, blockchain-based applications, or Web3 integrations.
Interest in agentic engineering, including emerging patterns in autonomous systems, tooling, or workflows, and their security implications.

Responsibilities

Conduct threat modelling reviews of Technical Design Documents (TDDs) for new and existing features, providing clear, actionable security recommendations early in the design process.
Perform and support application security assessments, including penetration testing, vulnerability assessments, and proof-of-concept (PoC) development where appropriate.
Investigate, triage, and respond to Bug Bounty program submissions, validating findings and working with engineering teams to drive timely remediation.
Own and continuously improve application-layer protections, including managing and tuning Cloudflare WAF and related security controls.
Partner closely with engineering teams to embed security best practices throughout the SDLC, from design and development through deployment and maintenance.
Research and track emerging threats and vulnerabilities, translating findings into practical mitigation strategies relevant to our technology stack.
Develop and deliver security guidance, training, and awareness for engineering teams to raise the overall security maturity of the organization.
Contribute to the creation, maintenance, and evolution of security standards, processes, and documentation.
Participate in and eventually lead incident response activities, supporting investigation, containment, remediation, and post-incident improvements.