As the first Senior Software Security Engineer at Harmonic Security Inc., you will own platform security architecture and write production code to harden core systems. Moving beyond generalist engineering, you will establish standards for authentication, encryption, and multi-tenant isolation. This hands-on role is for builders who prefer architecting secure solutions over auditing existing code.
Senior Software Security Engineer at Harmonic Security Inc.
Recently named a "Rising in Cyber 2026" leader, we are building the mission-critical infrastructure that allows enterprises to adopt AI safely and at scale. If you are a Java-fluent engineer who would rather build a secure architecture from the ground up than audit someone else's work, this is your chance to lead the security roadmap for a category-defining AI governance platform. Based in London, you will receive meaningful equity and the autonomy to shape our platform's security culture from day one.
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Location
London, United Kingdom
Compensation
£98k-£115k + Equity
Company
Harmonic Security Inc.
Role overview
Harmonic Security provides an AI Governance and Control (AIGC) platform that enables enterprises to adopt AI tools safely without risking data security and privacy. The company offers a ‘zero-touch’ data protection platform utilizing pre-trained, specialized large language models to detect sensitive data with high accuracy. Key offerings include Harmonic Protect, a data protection platform for secure AI adoption, and MCP Gateway, a developer-friendly gateway providing visibility and control over agentic AI ecosystems. The platform addresses ‘Shadow AI’ by offering continuous monitoring of unapproved AI tools, assessing associated risks, and allowing security teams to manage access and block sensitive content from being uploaded. Harmonic employs an end-user ‘nudging’ approach to guide safe AI usage alongside traditional security enforcement.
What you will do
- Take formal ownership of security architecture, including secrets management, multi-tenant isolation, and encryption at rest and in transit across the platform.
- Write high-quality production code in Java, Terraform, and Python to harden and extend security patterns within the core AI Governance and Control systems.
- Perform comprehensive threat modeling and architecture reviews for major new systems to ensure security is designed in from the start rather than retrofitted.
Who this is a fit for
- Has 6+ years of hands-on software engineering experience with a deep specialization in security architecture rather than general backend development or auditing.
- Possesses expert knowledge of Java, infrastructure-as-code using Terraform or OpenTofu, and AWS security fundamentals such as IAM and container management.
- Demonstrates a secure-by-design mindset and experience hardening SaaS platforms that face enterprise scrutiny, such as SOC 2 or ISO 27001 compliance standards.
Why this role is remarkable
- Join an early-stage, category-defining company named to “Rising in Cyber 2026,” tackling one of the enterprise world’s most urgent unsolved AI security challenges.
- Gain significant autonomy and ownership as the first dedicated security specialist, with the mandate to set technical standards that shape the company’s engineering future.
- Work in a high-trust, AI-first environment with meaningful equity, competitive bonuses, and annual global off-sites to destinations like Lisbon and Nashville.
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