Staff Application Security Engineer

Overview 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 lending, savings and trading products to digital asset holders in over 150 countries. The core values are integrity, ownership, progress, and empathy. Ledn is looking for a Staff Application Security Engineer to strengthen the security of our Bitcoin-backed loan platform. Responsibilities Lead 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 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. What You Bring To Ledn 10 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. Deep understanding of Linux internals. Ability to remediate vulnerabilities identified in penetration tests and strong communication to influence engineering and product teams. Nice To Haves Familiarity 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 We value leadership that thrives in startup or tech environments and embodies our values. The ideal candidate will be adaptable, resilient, and comfortable navigating ambiguity in a high-growth, fast-paced environment. Builder's mindset to create, iterate, and scale IS practices. Collaborative partner who can influence across functions and cultures with empathy and clarity. Demonstrates integrity and accountability, especially in managing confidential information across diverse contexts. Experience working in a remote environment. A Taste Of What We Provide Comprehensive, best-in-class total rewards package that starts on your first day. Competitive PTO package. Ownership in the company through shared equity. Ability to work remotely anywhere in the world for up to 180 days (subject to restrictions). Meaningful work that provides purpose in your job. We are an equal opportunity employment organization and pride ourselves on inclusivity and diversity. For accommodation requests during recruitment, please contact Ledn confidentially. Ledn is remote-first with a global team across North America, Latin America, South Africa, and Europe. Note: 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. #J-18808-Ljbffr