Staff Application Security Engineer

Overview Join 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 a passionate group of individuals from diverse backgrounds bonded by a conviction that digital assets can democratize access to the global economy. Ledn is guided by core values: act with integrity, own it, have a passion for progress, and lead with empathy. 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. This is a hands-on engineering role with direct impact on product security, infrastructure security, and customer trust. The Opportunity 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. Design and operate AWS Nitro Enclaves to protect critical data and cryptographic operations in isolated, verifiable environments. Responsibilities span application security, authentication/identity, confidential computing, and additional security domains across our cloud and development environments. 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 (e.g., 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 using AWS Nitro Enclaves; integrate 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. Qualifications 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. Strong communication and collaboration skills, able to influence engineering and product teams. Nice to Have 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 & Benefits We’re looking for a leader who thrives in a startup or tech environment and embodies our values. The ideal candidate will be adaptable, resilient, collaborative, and able to influence across functions with empathy and clarity. The role offers meaningful growth opportunities and a comprehensive rewards package, with remote-friendly options and equity ownership in Ledn. EEO & Employment Details Ledn is an equal opportunity employer and values inclusivity and diversity. You may reach out to the Ledn team by emailing for accommodation requests during all stages of the recruitment process. Requests will be addressed confidentially. We are a remote-first company with global teams; only qualified applicants will be contacted due to high volume. No agencies or recruiters, please. No unsolicited agency resumes or related fees. Location & Application Notes Get notified about new Application Security Engineer jobs in Curitiba, Paraná, Brazil. #J-18808-Ljbffr