Staff Application Security Engineer

Who Are We Looking For?

We are looking for a Staff Application Security Engineer to help secure the applications and identity integrations that power our products. This role will focus on analyzing and protecting our NestJS applications, strengthening application security practices across the software development lifecycle, and owning the security of our identity capabilities as both an identity provider (IdP) and a relying party (RP) in OIDC integrations and internal application usage.

You will work closely with software engineering, platform, infrastructure, and product teams to identify risk early, design practical mitigations, and make secure-by-default development easier. The ideal candidate combines strong hands-on application security skills with deep knowledge of modern authentication and authorization protocols.

What Will You Be Doing?

• Analyze NestJS and TypeScript applications for authentication, authorization, input validation, injection, session, API, business-logic, and data-protection vulnerabilities.
• Establish and evolve secure development patterns for NestJS, including guards, interceptors, middleware, decorators, validation, error handling, logging, configuration, and dependency management.
• Own or contribute to the security architecture of our OIDC integrations and identity platform capabilities when we operate as:
• An identity provider, including authorization, token, user-info, discovery, key-set, and logout endpoints.
• A relying party, including client registration, redirect handling, authorization-code flows, token exchange, session establishment, and logout.
• Design, review, and assess OAuth 2.0 and OpenID Connect flows, including authorization code with PKCE, refresh tokens, client authentication, scopes, consent, state, nonce, redirect URI validation, token lifetimes, and key rotation.
• Help define and enforce authorization models using RBAC and, where appropriate, claims-based or policy-based access control.
• Review access-control boundaries across services, APIs, tenants, users, roles, permissions, and administrative functions.
• Lead or participate in threat modeling, security design reviews, architecture reviews, and secure code reviews.
• Build security requirements, reusable libraries, reference implementations, and developer guidance that reduce recurring risk.
• Improve security testing and detection through SAST, DAST, software composition analysis, secret scanning, API testing, dependency monitoring, and targeted security testing.
• Partner with engineering teams to remediate vulnerabilities, prioritize findings by exploitability and business impact, and verify fixes.
• Monitor relevant application and identity security signals, support incident investigations, and contribute to playbooks for account takeover, token compromise, authorization bypass, credential abuse, and related events.
• Help maintain security documentation, standards, risk exceptions, and evidence needed for audits and customer assurance.
• Stay current on application security, identity, OAuth/OIDC, browser security, API security, cloud security, and emerging attack techniques.

Requirements

The Necessities

• Professional experience in application security, product security, software engineering, or a closely related discipline.
• Strong experience securing Node.js and TypeScript applications; hands-on experience with NestJS is required or highly preferred.
• Deep understanding of OAuth 2.0 and OpenID Connect, including common implementation pitfalls and secure deployment patterns.
• Practical experience with both IdP and RP implementations, integrations, or security assessments.
• Strong understanding of authentication and authorization concepts, including RBAC, least privilege, separation of duties, claims, scopes, permissions, sessions, tokens, and service-to-service access.
• Ability to review code and architecture across APIs, web applications, background jobs, and distributed services.
• Experience with web and API security risks, including OWASP Top 10, OWASP API Security Top 10, broken access control, SSRF, injection, XSS, CSRF, insecure deserialization, request forgery, misconfiguration, and supply-chain risk.
• Familiarity with secure token handling, JWT validation, key management, JWKS, signing algorithms, rotation, revocation, and token storage considerations.
• Experience integrating security into CI/CD and developer workflows without creating unnecessary friction.
• Strong communication skills and the ability to explain security risks and tradeoffs to both technical and non-technical audiences.
• A pragmatic, collaborative approach: you can identify meaningful risk, propose proportional controls, and help teams implement them.

The Extras

• Experience with OAuth 2.1 guidance, FAPI, PAR, JAR, DPoP, sender-constrained tokens, or other advanced OAuth security patterns.
• Experience with identity platforms or libraries such as Auth0, Okta, Keycloak, Cognito, Azure AD/Entra ID, or comparable systems.
• Experience with SAML integrations for single sign-on solutions.
• Experience with API gateways, service meshes, microservices, event-driven systems, and cloud-native deployments.
• Familiarity containers, infrastructure as code, secrets management, and cloud IAM.
• Experience with security tooling such as Burp Suite, Semgrep, CodeQL, Snyk, Dependabot, OWASP ZAP, or equivalent tools.
• Familiarity with security standards and guidance such as OWASP ASVS, OWASP SAMM, NIST SSDF, NIST 800-63, and relevant OAuth/OIDC specifications.
• Experience conducting penetration tests, adversarial reviews, or purple-team exercises.
• Relevant security certifications or equivalent demonstrated experience.

This role will be based in either the New York City, Austin, King of Prussia, or Scottsdale office, and will be part of Vestwell's hybrid in-office operation.

The expected base salary range for this position is $190K - $200K base. This position is eligible to participate in the Company Bonus Pool and is eligible to receive new hire equity in the Company. Please note that salary bands are based on NY and other similar metro areas and may differ based on where the role is ultimately hired.