[Remote] Senior Application Security Engineer

Note: The job is a remote job and is open to candidates in USA. MoonPay is a unified payments platform for digital currency, aiming to onboard the world to the decentralized economy. The Senior Application Security Engineer will strengthen systems through security reviews, penetration testing, and managing the Bug Bounty program while collaborating with engineering teams to embed security best practices throughout the software development lifecycle.

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

Skills

• You have 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
• You have hands-on experience performing white-box, source code-assisted web and mobile application penetration testing, from vulnerability discovery through triage and exploitation
• You have the ability to read, understand, and review source code to identify security issues, with ideally, a particular focus on JavaScript and TypeScript codebases
• You have a strong understanding of Threat Modelling principles and their practical application to the secure software development lifecycle (SDLC)
• You have experience working with web application firewalls to help protect applications, assess coverage, and support tuning rules to mitigate common attack patterns
• You have experience embedding application security practices into CI/CD pipelines, enabling early detection of vulnerabilities and close collaboration with engineering teams throughout the development lifecycle
• You have 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
• You are self-motivated, proactive, and take strong ownership of your work, operating effectively in a remote environment while maintaining a collaborative, team-focused mindset
• You have experience in JavaScript and TypeScript, including the ability to read, understand, and reason about modern web application codebases
• You have experience working with Cloudflare, including its hosting and Web Application Firewall (WAF) capabilities, to help secure and operate internet-facing applications
• You have experience testing and securing GraphQL, REST APIs, including understanding common GraphQL/REST-specific attack vectors and security considerations
• You have experience or a strong interest in Web3 security testing, including assessing smart contracts, blockchain-based applications, or Web3 integrations
• You have an interest in agentic engineering, including emerging patterns in autonomous systems, tooling, or workflows, and their security implications

Benefits

• Competitive salary package
• Equity package: We believe financial freedom starts with our employees, so all employees have ownership at MoonPay
• Pay for performance equity bonus: Those who drive outsized outcomes receive outsized rewards
• Moonshot award. We honor exceptional impact - 10 employees twice a year, each earning a $250,000 equity grant.
• Unlimited holidays: We give you the autonomy to choose when to work (and when to switch off)
• Hybrid working schedule: Work fully remotely or your nearest Moonbase, the choice is yours
• Private Healthcare benefits: To protect you and your loved ones
• Enhanced parental leave: So you can spend more time with your loved ones without a second thought
• Annual training budget: We support your training journey every step of the way
• Home office setup allowance: Create the home office of your dreams
• Remote working allowance: Those working fully remotely get a little extra for utilities
• Monthly budget to spend on our products and zero fee crypto transactions: Cultivate your inner DEGEN
• Employee referral programme: Great people know great people, refer them to receive 10K in USDC
• Regular remote company offsites: Meet your colleagues regularly for high impact in person sessions and hackathons
• Working in a disruptive and fast-growing company where excellence is rewarded

Company Overview

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