Staff Application Security Engineer

Overview Staff Application Security Engineer role at LEDN. Ledn is a global financial services company built for digital assets, offering egalitarian lending, savings and trading products to digital asset holders in over 150 countries. 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. Security is fundamental to protecting our customers and business, and this role will drive tactical improvements and long-term strategy for securing our applications and authentication systems. You will work across JavaScript/TypeScript services, AWS serverless stack (Lambda, API Gateway, Cognito, SNS, SQS), MongoDB and Kubernetes microservices, and evolve our authentication layer toward modern, phishing-resistant approaches. You will design and operate 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. About Ledn: we are a remote-first, global team with a culture built on integrity, ownership, progress, and empathy. We are committed to inclusivity and equality of opportunity. 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 MFA solutions (e.g., WebAuthn, passkeys, hardware tokens). Collaborate with Product to align usability, compliance, and security in authentication flows. Define secure session management, device trust, and account recovery approaches. 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. 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 of proven experience in Application Security for web and cloud-native applications. Strong knowledge of JavaScript/TypeScript/Golang/Python and modern web vulnerabilities (OWASP Top 10, auth bypasses, security flaws). Expertise with AWS security, especially serverless architectures. Hands-on experience with AWS Nitro Enclaves for confidential computing. Deep understanding of authentication/authorization standards (OAuth2, OIDC, WebAuthn, FIDO2). 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 Linux internals knowledge; ability to remediate vulnerabilities from pen tests. Strong communication and collaboration skills to influence across engineering and product teams. Nice To Haves Familiarity with Bitcoin custody and key management practices. Knowledge of Infrastructure as Code security (Terraform, AWS CDK). Experience with user-facing security features such as passwordless authentication, recovery flows, or device trust. Culture Fit and The Ideal Candidate Leadership with a startup/tech mindset; thrives in a high-growth, fast-paced environment. Builder’s mindset: eager to create, iterate, and scale information security practices. Collaborative and empathetic, capable of influencing across functions and cultures. Demonstrates integrity and accountability, especially with confidential information across diverse contexts. Experience working in a remote environment. What We Provide Growth opportunities at a leading digital asset company. Comprehensive, best-in-class total rewards package starting on day one. Competitive PTO and ownership via equity; remote work flexibility up to 180 days per year (subject to restrictions). A purpose-driven role with a team that removes barriers to doing great work. Equal opportunity employer; inclusive and diverse culture; accommodation requests welcomed at all stages of recruitment. Additional Details Location: Remote-friendly; positions open in multiple regions. Due to high application volume, only qualified applicants will be contacted. Shortlisted candidates may be asked to submit a short video and we may review publicly available social media activity relevant to the role. No agencies or recruiters; unsolicited resumes are not accepted. #J-18808-Ljbffr