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. Ledn offers egalitarian lending, savings and trading products to digital asset holders in over 150 countries. Ledn is committed to integrity, accountability, progress, and empathy, and seeks to build a diverse team that can democratize access to the global economy through digital assets. The OpportunityWe 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; this role will drive tactical improvements and long-term strategy for securing applications and authentication systems. 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 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. 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, 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 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 and remediation of vulnerabilities identified in penetration tests. Strong communication and collaboration skills, able 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 a startup or tech environment, embodies our values, and is adaptable, resilient, and able to navigate ambiguity. Be a builder with a mindset to create, iterate, and scale information security practices. Collaborate across functions and cultures with empathy and clarity; demonstrate integrity and accountability for confidential information. Experience working in a remote environment. What We ProvideGrowth opportunities and a comprehensive total rewards package that starts on day one. Competitive PTO and ownership in the company through equity; remote work up to 180 days (subject to restrictions). A role with purpose in a global digital asset company; a remote-first environment. EEO & Application DetailsLedn is an equal opportunity employer committed to inclusivity and diversity. No agencies or recruiters; unsolicited resumes are not accepted. Due to high application volume, only those who qualify will be contacted. Shortlisted candidates may be asked to submit a short video response and Ledn may review publicly available social media activity relevant to the role. #J-18808-Ljbffr