Staff Application Security Engineer

OverviewStaff 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 is a full-time role focused on securing applications, authentication systems, and related infrastructure at Ledn. Ledn is a global financial services company built for digital assets, helping to improve the everyday lives of Bitcoin holders while building generational wealth. We offer lending, savings and trading products to digital asset holders in over 150 countries. Our values emphasize integrity, ownership, progress, and empathy. We are a remote-first, globally distributed team. 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. Remediate vulnerabilities and improve secure development practices in collaboration with engineers. 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 and 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 communication and collaboration skills, able 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 FitWe are looking for a leader who thrives in a startup or tech environment and embodies our values, with a builder’s mindset, adaptability, and resilience in a high-growth, fast-paced setting. A collaborative partner who can influence across functions and cultures with empathy and clarity, and who demonstrates integrity and accountability in handling confidential information. The Ideal Candidate WillBe adaptable and resilient, comfortable navigating ambiguity; have a builder's mindset to create, iterate, and scale security practices; collaborate across teams; and have remote-work experience. BenefitsComprehensive, best-in-class total rewards package starting on day one, including a competitive PTO package, ownership in the company via shared equity, and remote work flexibility up to 180 days per year (subject to restrictions). Ledn is an equal opportunity employer and values inclusivity and diversity. Application NotesLedn is a remote-first company with teams across North America, Latin America, South Africa and Europe. Due to high application volume, only qualified applicants will be contacted. Shortlisted candidates may be asked to submit a short video response and may have their publicly available social media activity reviewed. No agencies or recruiters please; unsolicited resumes are not accepted. For accommodation requests, please contact Ledn confidentially. #J-18808-Ljbffr