Staff Application Security Engineer

Overview Staff Application Security Engineer at LEDN. Ledn is a global financial services company built for digital assets, offering lending, savings and trading products to digital asset holders in over 150 countries. This is a full-time role focused on strengthening the security of Ledn\'s Bitcoin-backed loan platform through hands-on engineering and security leadership. The role involves working across JavaScript/TypeScript services, AWS serverless stack (Lambda, API Gateway, Cognito, SNS, SQS), MongoDB and Kubernetes microservices, and evolving the authentication layer toward modern, phishing-resistant approaches. The position also includes designing and operating AWS Nitro Enclaves to protect critical data and cryptographic operations in isolated environments. This is a hands-on engineering role with direct impact on product security, infrastructure security, and customer trust. 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, 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 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. Understanding of software supply chain. Deep understanding of Linux internals. Remediate vulnerabilities identified in the penetration test report. Strong communication and collaboration skills, able 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\'re looking for more than just operational excellence — we want a leader who thrives in the startup or tech environment and embodies our values. Have a passion for progress by being adaptable and resilient, and comfortable navigating ambiguity in a high-growth, fast-paced environment. Have a builder\'s mindset, excited to create, iterate, and scale IS practices. Be a collaborative partner, able to influence across functions and cultures with empathy and clarity. Demonstrate integrity and accountability, especially in managing confidential information across diverse legal and cultural contexts. Have worked in a remote environment before. 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. Remote work flexibility for up to 180 days (subject to restrictions). A career that provides purpose and removes barriers so you love what you do. We are an equal opportunity employment organization and pride ourselves on inclusivity and diversity. You may reach out to the Ledn team by emailing for accommodation requests throughout all stages of the recruitment process. Requests will be addressed confidentially. Ledn Working Environment: Our team is global and remote-first. 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 resumes. #J-18808-Ljbffr