Staff Application Security Engineer

OverviewJoin to apply for the Staff 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 for the future. We offer a suite of egalitarian lending, savings and trading products to digital asset holders in over 150 countries around the world. Our team is diverse and committed to values including integrity, progress, and empathy. We are remote-first and globally distributed. 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, and this role will drive both the 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. In addition, 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. 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 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; ensure compliance, auditability, and resilience. Harden AWS services with least-privilege IAM and secure key management; improve Kubernetes security posture; deploy and operate a SIEM framework; support compliance initiatives (SOC 2, ISO 27001). Qualifications10+ 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). 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; remediation of vulnerabilities identified in penetration tests. Strong communication and collaboration skills. Nice To HavesFamiliarity 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 FitWe\'re looking for more than operational excellence — we want a leader who thrives in the startup or tech environment and embodies our values. The Ideal Candidate WillBe adaptable and resilient, able to navigate ambiguity in a high-growth, fast-paced environment. Have a builder\'s mindset 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 handling confidential information across diverse contexts. Have remote-work experience. A Taste Of What We ProvideGrowth opportunities; comprehensive total rewards package starting on day one. Competitive PTO and ownership in the company via equity; remote work options up to 180 days. A purpose-driven career; inclusive, diverse culture; ability to accommodate requests confidentially during recruitment. EEO Statement: We are an equal opportunity employment organization and pride ourselves on inclusivity, diversity, and the success that comes from diversity. You may reach out to the Ledn team 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 shortlisted candidates will be contacted. As part of our selection process, you 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. We do not accept unsolicited resumes. Locations mentioned: Brusque, Blumenau, Gaspar, Itapema, Tijucas, Navegantes, Porto Belo, Santa Catarina, Brazil. #J-18808-Ljbffr