Staff Application Security Engineer

OverviewStaff 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. 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. Security is fundamental to protecting our customers and business. 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, verifiable environments. 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 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; integrate Nitro Enclaves 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. Deep understanding of Linux internals. Remediate vulnerabilities identified in penetration test reports. Strong 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 & The Ideal CandidateWe seek a leader who thrives in startup or tech environments and embodies our values: act with integrity, own it, have a passion for progress, and lead with empathy. Have a passion for progress by being adaptable and resilient in a high-growth, fast-paced environment. Be a builder with a mindset to create, iterate, and scale information security practices. Be a collaborative partner, able to influence across functions and cultures with empathy and clarity. Demonstrate integrity and accountability in managing confidential information across diverse contexts. Experience working in a remote environment. What We ProvideComprehensive, best-in-class total rewards package that starts on your first day. Competitive PTO and ownership in the company through shared equity. Remote work option up to 180 days per year (subject to restrictions). A purpose-driven career and supportive environment that removes barriers to doing great work. Equal opportunity employer; we value inclusivity and diversity. You may reach out to the Ledn team regarding accommodation requests throughout all stages of the recruitment process. Requests will be addressed confidentially. Ledn operates a remote-first environment with a global team across North America, Latin America, South Africa and Europe. 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; unsolicited resumes will not be accepted. #J-18808-Ljbffr