Senior Application Security Engineer

Rain is the fastest-growing earned wage access (EWA) fintech in the U.S., serving 3.5 million employees and backed by top investors like QED and Prosus. We’ve raised nearly $400M in funding—including the largest Series A in fintech history—and just closed our Series B to fuel our next stage of hypergrowth.

We are seeking a skilled and driven Senior Application Security Engineer to join Rain’s growing Security team. This role demands a proactive approach to secure software development and cloud‑native defense. You will partner closely with engineering and development squads, and work alongside our Cloud Security and GRC team members to improve Rain’s application and platform security posture.

This position is technically grounded, requiring direct engagement in application‑layer matters and security reviews, while also contributing to cloud security automation, awareness initiatives, and secure engineering practices across the SDLC.

• Collaborate with development squads to validate vulnerabilities and provide actionable remediation guidance aligned with business risk.
• Drive threat modeling sessions (e.g., STRIDE, PASTA) for critical systems and APIs.
• Design, implement, and oversee automated processes for securely updating application and code dependencies, proactively mitigating issues and ensuring timely vulnerability remediation.
• Integrate security checks into CI/CD pipelines (SAST, DAST, SCA, IaC), working with tools like Semgrep, Snyk, Trivy, and Burp Suite.
• Contribute to runtime security initiatives, such as container/Kubernetes hardening, RASP, and eBPF-based detection.
• Build and maintain a security issues dashboard to track remediation status and metrics.
• Provide real‑time support in the event of cybersecurity incidents impacting applications or cloud infrastructure (exploited vuln, credential stuffing, web/API attacks).
• Partner with the Cloud Security team on security automation tasks and monitoring improvements (e.g., Security Hub remediation automations, DLP monitoring, etc.).
• Conduct proactive research on new threats, vulnerabilities, and attack techniques relevant to Rain’s architecture.
• Collaborate with the GRC team to develop and deliver internal security awareness initiatives, phishing campaigns, and developer training (e.g., secure coding, API security).
• Participate in the continuous improvement of App Sec maturity (e.g., aligning with OWASP SAMM, ISO 27001, or SOC 2 frameworks).

• Strong problem‑solving and analytical mindset.
• Excellent communication skills to convey security risks to technical and non‑technical stakeholders.
• 3–5+ years of experience in application security, penetration testing roles, and/or secure code development, including work with QA teams.
• Hands‑on experience with SAST, DAST, and SCA tools (e.g., Semgrep, Burp, Snyk).
• Deep understanding of web, mobile, and API vulnerabilities (OWASP Top 10, API Top 10, MITRE CWE).
• Proven expertise in performing code review or security assessments and writing clear reports.
• Proficiency in at least one back‑end language (e.g., Go, Python, Node.js) and understanding of React / React Native front‑ends.
• Familiarity with secure architecture of microservices, event‑driven systems, and REST APIs using OAuth2/OpenID Connect.
• Experience securing CI/CD pipelines and integrating App Sec tooling into SDLC.
• Solid knowledge of containerization and Kubernetes security fundamentals.
• Understanding of cloud security (preferably AWS), including IAM principles, cloud‑native service configurations, and network segmentation.
• Comfortable with Agile development methodologies and working within cross‑functional squads.
• Software supply chain security (e.g., SBOM, artifact signing).

• Certifications such as OSCP, OSWE, GWAPT, CPTE, or CSSLP.
• AWS, GCP, or Azure Security Specialty certification.
• Familiarity with bug bounty triage and vulnerability management platforms (e.g., Defect Dojo).
• Experience implementing RASP or eBPF runtime protection tools.
• Exposure to LLM/AI security considerations and secure code generation practices.
• Familiarity with logging and monitoring tools (e.g., Cloud Watch, Datadog, Grafana).