Staff Application Security Engineer

Overview Staff Application Security Engineers, Ledn is seeking a full-time professional with deep expertise in Application Security, Identity & Access Management, and Confidential Computing to strengthen the security of our Bitcoin-backed loan platform. This hands-on role has direct impact on product security, infrastructure security, and customer trust. The Opportunity Ledn is a global financial services company for digital assets, offering lending, savings and trading products in over 150 countries. You will work across our 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, verifiable 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 (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 security controls and documentation for compliance initiatives (SOC 2, ISO 27001). 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 and remediation of vulnerabilities identified in penetration tests. 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). Experience with user-facing security features such as passwordless authentication, recovery flows, or device trust. Culture Fit We’re looking for a leader who thrives in a startup or tech environment and embodies our values: integrity, ownership, progress, and empathy. Be adaptable and resilient, comfortable 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 empathy and clarity. Demonstrate integrity and accountability in managing confidential information across diverse contexts. Have experience working in a remote environment. What We Provide Comprehensive, best-in-class total rewards package beginning on day one. Competitive PTO and ownership in the company through shared equity. Ability to work remotely from anywhere in the world for up to 180 days (subject to restrictions). Purpose-driven work removing barriers so you love what you do. We are an equal opportunity employer and value inclusivity and diversity. You may reach out to the Ledn team by email for accommodation requests throughout the recruitment process. Requests will be addressed confidentially. Ledn Working Environment: We are a globally distributed, remote-first team. Please note that due to high application volumes, not all 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, and we do not accept unsolicited resumes. #J-18808-Ljbffr