Sr. Application Security Engineer

We are seeking a Sr. Application Security Engineer to join our security team. In this role, you will be a critical partner to engineering, product, and DevOps teams, helping to identify, assess, and mitigate security risks across the software development lifecycle (SDLC). You will drive security by design, shape our product security standards, and ensure vulnerabilities are identified, tracked, and resolved efficiently.
This is a hands-on technical role where you will lead secure architecture/design reviews, code reviews, and penetration testing while collaborating closely with teams to embed security in every phase of product development.
The expected working hours for this role are based in Pacific Time.

Problems You Will Solve

• Partner with engineering and product teams to define and implement security requirements for applications, APIs, and microservices during design and architecture reviews.
• Conduct in-house penetration testing, secure code reviews, and threat modeling for high-impact features and critical products.
• Lead application vulnerability management, including triaging and driving the remediation of security findings from SAST, DAST, SCA, and penetration tests.
• Consult and advise cross-functional teams (engineering, DevOps, product) on secure coding practices, security architecture, and remediation strategies.
• Establish and maintain application security standards, guidelines, and best practices, aligned with OWASP, NIST, ISO, and industry frameworks.
• Ensure vulnerabilities are classified, prioritized, and remediated according to vulnerability management policies and regulatory requirements.
• Work closely with DevSecOps teams to ensure SAST/DAST/IAST/SCA tools are integrated into CI/CD pipelines and functioning effectively.
• Track and manage security issues to resolution, providing metrics, reports, and dashboards for leadership visibility.
• Stay up-to-date with emerging security threats, vulnerabilities, tools, and methodologies to continuously improve Prosper’s security posture.

All About You

• Bachelor’s degree in Computer Science, Information Security, or related field, with 8+ years of relevant experience (or Master’s degree with 6+ years).
• Strong hands-on experience in application security, secure coding, and penetration testing.
• Development background with expertise in Java/Python, SQL, JavaScript, HTML and experience reviewing modern application architectures.
• Experience working with modern web application frameworks (e.g., Spring Boot, .NET, J2EE, Rails, REST, SOAP).
• In-depth understanding of web and API security vulnerabilities (e.g., OWASP Top 10, API Top 10, CWE).
• Familiarity with authentication and authorization protocols (e.g., OAuth2, OIDC, SAML).
• Knowledge of application security testing tools (SAST, DAST, SCA, IAST) and methodologies.
• Proven experience working with DevOps/DevSecOps pipelines, integrating security tools and automation.
• Strong understanding of vulnerability management processes and regulatory frameworks (e.g., PCI DSS, GDPR, SOC 2).
• Bonus: Knowledge of cloud security (AWS, GCP, Azure) and container security (Docker, Kubernetes).
• Security experience in Agile, CI/CD, and fast-paced product development environments.
• Preferred: Industry certifications such as OSCP, CSSLP, GWAPT, CEH, GPEN, CISSP.
• Preferred: Familiarity with mobile application security testing and API security testing tools (e.g., Burp Suite, Postman, ZAP, Insomnia).
• Preferred: Knowledge of network security, infrastructure security, and microservices architecture.
• Preferred: Experience driving secure SDLC initiatives and developer security education.

What We Offer

• The opportunity to collaborate with a team of creative, fun, and driven colleagues on products that have an immediate and significant impact on people's lives
• The opportunity to work in a fast-paced environment with experienced industry leaders
• Flexible time off, comprehensive health coverage, competitive salary, paid parental leave
• Wellness benefits including access to mental health resources, virtual HIIT and yoga workouts
• A bevy of other perks including Udemy access, childcare assistance, pet insurance discounts, legal assistance, and additional discounts

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About Our Technology TeamWe are growing our Technology team to support our various financial products. The ideal candidate is passionate about learning the Fintech domain and delivering cutting-edge, high-quality solutions to solve business problems. We utilize a progressive, test-driven, Agile development methodology that places a high premium on communication, teamwork, sou