Principal Software Engineer, Autonomous Defense

The role

You will lead the technical work for NodeZero's defensive agents. You will set technical direction, write production code, and mentor engineers through architecture and design review.

What you will do

• Own the end-to-end technical vision for the workstream
• Contribute production code in a modern backend language
• Set and raise the technical bar through design reviews and code quality
• Mentor and enhance engineers
• Translate ambiguous product goals into concrete technical roadmaps
• Make build vs. buy vs. integrate decisions
• Design durable execution for long-running, resumable agent runs
• Design the tool and authorization layer for tenant scope and permissions
• Own multi-tenant isolation for agents that take write actions
• Architect the connector framework over heterogeneous third-party security control APIs

Required qualifications

• Bachelor's Degree in Computer Science, Computer Engineering or related field
• 10+ yrs professional software engineering experience using modern object-oriented or functional languages (Python, Go, Scala, C++, TypeScript, etc)
• Experience building applications on cloud computing platforms such as AWS, Azure, GCP, using container technologies such as Docker and Kubernetes
• Deep experience with agentic or LLM-backed systems in production
• Expert proficiency in SQL
• Demonstrated experience designing and operating distributed systems in production
• A track record of shipping and operating production services, including on-call ownership

Nice to have

• Experience with a durable execution (such as Temporal) or workflow engine or having built equivalent checkpointing yourself
• Experience building multi-tenant platforms with hard isolation requirements, workload identity, and short-lived credential brokering
• Experience integrating a long tail of third-party APIs behind a normalized abstraction
• Familiarity with security control planes and their APIs — EDR (CrowdStrike, SentinelOne, Microsoft Defender), firewalls, SIEM, cloud IAM
• Experience with database architectures including relational (PostgreSQL) and graph (Neo4j), and experience building GraphQL backends

Benefits

• Equity package in the form of stock options
• Health, vision & dental insurance for you and your family
• Flexible vacation policy
• Generous parental leave

About the company

Horizon3 is a fast-growing, remote cybersecurity company dedicated to the mission of enabling organizations to proactively find and fix and verify exploitable attack vectors. Their flagship product is the NodeZeroTM platform.