Staff Application Security Engineer

Overview Join to apply for the Staff Application Security Engineer role 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 for the future. We offer a suite of egalitarian lending, savings and trading products to digital asset holders in over 150 countries around the world. Our team is diverse and values integrity, ownership, progress, and empathy. Ledn is remote-first and supports global teams. 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 is a hands-on engineering role with direct impact on product security, infrastructure security, and customer trust. You will work across our JavaScript/TypeScript services, AWS serverless stack (Lambda, API Gateway, Cognito, SNS, SQS), MongoDB and Kubernetes microservices, and take ownership of evolving 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 environments. Role scope includes secure design, code reviews, vulnerability automation (SAST, SCA, DAST), threat modeling, and collaboration with engineers to remediate vulnerabilities and improve secure development practices. 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 (e.g., 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 and resilience. 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. Qualifications 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 and ability to remediate vulnerabilities identified in penetration test reports. Strong communication and collaboration skills 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, adaptability, resilience, and collaboration in a startup/tech environment and expect empathy and clarity in cross-functional work. The Ideal Candidate Will Have a passion for progress, adaptability, and comfort navigating ambiguity in a high-growth, fast-paced environment. Have a builder's mindset to create, iterate, and scale information security practices. Be a collaborative partner able to influence across functions and cultures with integrity and accountability, especially for confidential information. Have experience working in a remote environment. A Taste Of What We Provide Tremendous growth 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 flexibility: work remotely anywhere in the world for up to 180 days (subject to restrictions). A purposeful career that removes barriers to doing meaningful work. We are an equal opportunity employer, committed to inclusivity and diversity. You may contact the Ledn team for accommodation requests at any stage of the recruitment process. Requests will be addressed confidentially. Ledn Working Environment: Our team is global with remote-first culture across North America, Latin America, South Africa and Europe. Please 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. #J-18808-Ljbffr