Staff Application Security Engineer

Ever since we started in 2007, Sunrun has been at the forefront of connecting people to the cleanest energy on Earth. It's why we've become the #1 home solar and battery company in America. Today, we're on a mission to change the way the world interacts with energy, and we're building a company and brand that puts power at the center of life. And we're doing it by designing a dynamic culture where employee development, well-being, and safety come first. We're unlike any other solar company. Our vertically integrated model gives us total control over every part of the energy lifecycle - from sale through installation and beyond - so you can find endless opportunities for growth. Come join a career you can grow in and a culture you can run with.

This position is primarily remote, with occasional visits to a local office or our corporate headquarters for team-building, training, and collaborative project work. These on-site sessions are designed to strengthen connections, share insights, and ensure a seamless experience for our team and customers. Equipment pick-up from a local branch will be required. We will provide advance notice whenever on-site attendance is required, making these times purposeful and rewarding.

Position Overview:

The Application Security Engineer at Sunrun plays a pivotal role in protecting the applications that power our business. This position requires expertise across identity systems, and software development lifecycle. You will be responsible for driving the identification, assessment, and mitigation of security risks from the initial design phase through deployment and beyond. You will collaborate closely with developers and IT teams to integrate robust security practices, implement advanced protective measures for both applications and identities, and foster a comprehensive culture of security across the organization.

Key Responsibilities

• Threat Modeling & Security Design: Assess potential attack vectors and design defense-in-depth strategies that address gaps across infrastructure, 1st and 3rd party applications, and identity management.
• Secure Software Development Life Cycle (SSDLC): Partner with application development teams to integrate security into every stage of the development lifecycle. Champion secure coding standards, conduct security code reviews, and provide expert guidance to minimize vulnerabilities before production.
• Identity & Access Management (IAM): Design, implement, and manage identity security solutions across 1st and 3rd party applications. Showcase hands-on experience in implementing strategies like Zero Trust architecture and modern authentication standards like WebAuthn.
• Implement & Manage Security Controls: Design, implement, and fine-tune application security controls like SAST/DAST vulnerability scanning andand standardizing secure coding practices. Establish and improve operational processes to ensure their continued effectiveness.
• Guidance, Training & Compliance: Develop and maintain security policies and standards for both application and identity security. Provide ongoing training to developers to elevate secure coding practices.
• Stakeholder Collaboration: Use strong critical thinking and communication skills to present complex technical concepts to business stakeholders, gain alignment, and independently drive security initiatives forward.

• 5+ years of combined experience in application security and identity & access management (IAM), with a proven track record of supporting application development teams.
• Deep knowledge of application security principles, secure coding practices, common vulnerabilities (e.g., OWASP Top 10), and zero-trust architecture.
• Hands-on experience with security testing tools (SAST, DAST), Web Application Firewalls (WAF), and IAM platforms (e.g., Okta, AWS IAM).
• Proficiency in programming languages such as Java, Python, or JavaScript.
• Strong familiarity with cloud environments (AWS, GCP) and their native security and identity controls.
• Demonstrated expertise in threat modeling and designing defense-in-depth strategies for complex applications.
• Solid understanding of modern identity standards and technologies, including MFA, SSO, and WebAuthn.
• Excellent communication and collaboration skills, with the ability to articulate technical findings and security risks to diverse audiences.
• Strong critical thinking and creative problem-solving skills, with the ability to analyze systems from an attacker's perspective and devise effective countermeasures.

• Experience with Okta and Salesforce security principles and best practices.
• Certifications (preferred): Certified Information Systems Security Professional (CISSP), Certified Application Security Engineer (CASE), or similar credentials.