Staff Application Security Engineer

OverviewStaff Application Security Engineers, Ledn is a global financial services company built for digital assets, helping to improve the everyday lives of Bitcoin holders while building generational wealth for the future. Ledn offers a suite of egalitarian lending, savings and trading products to digital asset holders in over 150 countries. Our team is diverse and values integrity, ownership, progress, and empathy. We are building, innovating and revolutionizing financial services to democratize access to the global economy. The Opportunity: We are seeking a full-time Staff Application Security Engineer with deep expertise in Application Security, Identity & Access Management, and Confidential Computing to strengthen the security of our Bitcoin-backed loan platform. This role will drive both tactical improvements and long-term strategy for securing our applications and authentication systems. You will work across our JavaScript/TypeScript services, AWS serverless stack (Lambda, API Gateway, Cognito, SNS, SQS), MongoDB and Kubernetes microservices, owning the evolution of our authentication layer toward modern, phishing-resistant approaches. You will also design and operate AWS Nitro Enclaves to protect critical data and cryptographic operations in isolated, verifiable environments. This is a hands-on engineering role with direct impact on product security, infrastructure security, and customer trust. ResponsibilitiesLead secure design and code reviews across engineering teams. Define and enforce secure coding practices for JavaScript/TypeScript services. Automate vulnerability detection (SAST, SCA, DAST) within CI/CD. Conduct threat modeling and risk assessments for new features. Partner with engineers to remediate vulnerabilities and improve secure development practices. Own the roadmap for authentication and identity across customer and internal applications. Enhance Cognito-based identity architecture with stronger, phishing-resistant MFA solutions (WebAuthn, passkeys, hardware tokens). Collaborate with Product to align usability, compliance, and security in authentication flows. Define secure approaches to session management, device trust, and account recovery. Design enclave-based architectures to isolate and protect sensitive workloads using AWS Nitro Enclaves; integrate with KMS and secure APIs; migrate high-value operations into enclave environments; ensure compliance, auditability, and resilience of enclave workloads. Harden AWS services (Lambda, API Gateway, SQS, SNS) with least-privilege IAM and secure key management. Improve Kubernetes security posture (RBAC, pod security, image scanning, runtime monitoring). Deploy and operate a SIEM framework; develop detection rules, dashboards, and incident playbooks. Support compliance initiatives (SOC 2, ISO 27001) with security controls and documentation. Qualifications10 years minimum of proven experience in Application Security with a focus on web and cloud-native applications. Strong knowledge of JavaScript/TypeScript/Golang/Python and modern web vulnerabilities (OWASP Top 10, auth bypasses, business logic flaws). Expertise with AWS security best practices, particularly in serverless architectures. Hands-on experience with AWS Nitro Enclaves for confidential computing. Deep understanding of authentication and authorization standards (OAuth2, OIDC, WebAuthn, FIDO2). Practical experience with Cognito / Auth0 (MFA, custom flows, secure session handling). Background in SIEM design and log correlation across cloud and application layers. Familiarity with Kubernetes security (RBAC, pod security, admission controls, image scanning). Experience with Secure Code Review and understanding of software supply chain. Strong knowledge of Linux internals and ability to remediate vulnerabilities identified in penetration tests. Excellent communication and collaboration skills to influence engineering and product teams. Nice To HavesFamiliarity with Bitcoin custody and key management practices. Knowledge of Infrastructure as Code security (Terraform, AWS CDK). Prior work on user-facing security features such as passwordless authentication, recovery flows, or device trust. Culture Fit & The Ideal CandidateWe’re looking for a leader who thrives in startup or tech environments and embodies our values of integrity, ownership, progress, and empathy. Have a passion for progress by being adaptable and resilient in a high-growth, fast-paced setting. Builder mindset: eager to create, iterate, and scale information security practices. Collaborative partner capable of influencing across functions and cultures with clarity and empathy. Demonstrate integrity and accountability, especially in managing confidential information across diverse legal and cultural contexts. Experience working in a remote environment. A Taste Of What We ProvideGrowth opportunities with a comprehensive, best-in-class total rewards package starting on day one. Competitive PTO and ownership in the company through shared equity. Remote work options worldwide (up to 180 days, subject to restrictions). A purpose-driven career and a culture that removes barriers so you can excel. Equal opportunity employment; Ledn values diversity and inclusion. We may request accommodation information at any stage of the recruitment process. All accommodation requests will be treated confidentially. Working EnvironmentLedn is truly global with team members across North America, Latin America, South Africa and Europe. We are a remote-first company. Please note that due to high volume of applications, only qualified applicants will be contacted. Shortlisted candidates may be asked to submit a short video response and we may review publicly available social media activity relevant to the role. No agencies or recruiters please. We do not accept unsolicited agency resumes and we are not responsible for any fees related to unsolicited resumes. #J-18808-Ljbffr