Staff Application Security Engineer

Overview 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. 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 both tactical improvements and long-term strategy for securing our 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 also 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. 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. Remediate vulnerabilities and improve secure development practices in collaboration with engineers. Own the roadmap for authentication and identity across customer and internal applications. Enhance Cognito-based identity architecture with stronger MFA solutions (WebAuthn, passkeys, hardware tokens). Collaborate with Product to balance 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; integrate Nitro Enclaves with KMS and secure APIs. Migrate high-value operations into enclave environments and ensure enclave workload compliance 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. Required Experience & Skills (What You Bring) 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). 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 chains. 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 & The Ideal Candidate We seek a leader who thrives in a startup or tech environment and embodies our values: act with integrity, own it, have a passion for progress, and lead with empathy. Have a builder's mindset, are adaptable and resilient, and comfortable navigating ambiguity in a high-growth, fast-paced environment. Demonstrate integrity and accountability, especially in managing confidential information across diverse legal and cultural contexts. Have experience working in a remote environment. A Taste Of What We Provide Comprehensive, best-in-class total rewards package that starts on your first day. Competitive PTO and ownership in the company; through shared equity, Ledn employees are stakeholders in the future of the digital economy. Remote-friendly option to work from anywhere in the world for up to 180 days (subject to restrictions). A role with purpose, growth opportunities, and a supportive environment focused on inclusivity and diversity. Equal opportunity employer. If you have accommodation requests throughout the recruitment process, you may reach out to the Ledn team confidentially. We are a remote-first global team and welcome applicants from diverse backgrounds. #J-18808-Ljbffr