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Juniper Square is the operations partner for private markets, serving 2,300+ GPs with a unified platform for technology, data, and fund administration. The company administers $300B+ in assets and operates at scale with 1,000+ employees across multiple continents. JunieAI, their purpose-built AI platform, is reimagining workflows across private markets.
As a Senior Engineer in Application and Platform Security on the Platform Engineering team, you will identify and remediate vulnerabilities across applications and cloud infrastructure, then build the automation, guardrails, and secure defaults that prevent recurrence. The role spans application code, build and deployment systems, cloud infrastructure, and AI-powered features. This is a hands-on position where you'll write production-quality code, ship tools that engineers want to use, and leverage AI agents to amplify your impact.
Key responsibilities include:
- Lead security design reviews and threat models for new product features, with expertise in authentication, authorization, data isolation, and high-risk financial workflows
- Perform manual code review and security testing of web applications and APIs, focusing on authorization and business logic flaws that automated scanners miss
- Design secure-by-default libraries, framework-level controls, and custom static analysis rules to eliminate vulnerability classes
- Triage findings from automated and manual testing and external assessments; group by root cause and provide remediation guidance
- Threat-model and test AI-powered product features against prompt injection, unsafe tool use, data leakage, and excessive agency risks
- Share design review and triage responsibilities across the team
- Support external penetration testing programs from scoping through retest
- Partner on build pipeline and supply-chain security, particularly dependency risk in application code
- Participate in incident response for application security events
- Build security automation and agents to reduce review and triage time
The company offers flexible work arrangements, ranging from fully remote to full-time office presence. Physical offices are located in San Francisco, New York City, Mumbai, and Bangalore, with operations spanning 27 U.S. states, 2 Canadian provinces, India, Luxembourg, and England.
REQUIREMENTS:
- 5+ years in application or product security, or in software engineering with a strong security focus
- Deep experience finding vulnerabilities through manual code review, particularly authorization and business logic flaws
- Strong Python proficiency; working proficiency in JavaScript/TypeScript for front-end code review
- Production-quality coding ability, not just scripting
- In-depth knowledge of OAuth 2.0/OIDC, SAML, MFA, session management, and access control models with hands-on implementation experience
- Experience leading threat modeling sessions with engineering teams and translating output into concrete requirements
- Experience running and tuning SAST, SCA, and DAST tools, including writing custom rules
- Working knowledge of cloud, container, and CI/CD security
- Working understanding of LLM application risks and commitment to developing deeper expertise
- Clear writing and demonstrated ability to influence engineering teams without becoming a bottleneck
NICE TO HAVE:
- Offensive web security background (bug bounty, web application CVEs, CTFs)
- Certifications such as OSWE or BSCP
- Experience building developer-facing security tooling or libraries
- Experience building or running a security champions program
- Familiarity with OWASP ASVS or OWASP Top 10 for LLM Applications
