Principal Software Engineer, Autonomous Defense Lead

OpenKrill; United States; Hybrid; USD 255,000 - 300,000; Full time

Benefits offered by this job

Inclusive culture

Career growth

Innovative environment

Hybrid/Remote work

Equity & benefits

Job summary

Horizon3 is seeking a Principal Software Engineer to lead the technical work for NodeZero's defensive agents, translating proven attack paths into continuous remediation. You will set direction with AI researchers and lead the engineers who build the platform underneath them.

This is a technical leadership role without direct people management. You will write production code weekly, review PRs, and partner with Product to sequence problems.

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 with a clear-eyed view of where they fail and how to contain it.
• Expert proficiency in SQL.
• Demonstrated experience designing and operating distributed systems in production: asynchronous workflows, queues, retries, idempotency, and partial failure.
• A track record of shipping and operating production services, including on-call ownership.

Responsibilities

• Owns the end-to-end technical vision for the workstream and rallies the team around it — from blank doc through shipping, iterating, and deprecating.
• Production code contributions at Lead/Principle level in a modern backend language (Python, Go, Rust, or similar) in a service-oriented environment.
• Sets and raises the technical bar (design reviews, code quality, operational discipline) by example rather than by mandate.
• Mentors and enhances the engineers around them; builds the frameworks and architecture for others to do the best work of their careers.
• Holds the team accountable to outcomes rather than activity; surfaces risks and tradeoffs early and in writing.
• Serves as the durable technical interface between AI research and platform engineering, so research direction accounts for platform constraints early rather than at handoff.
• Translates ambiguous product goals into concrete technical roadmaps.
• Makes build vs. buy vs. integrate calls with business context, not just engineering preference.
• Partners closely with PM — comfortable in PRD reviews, not just sprint planning.
• Sequences an MVP without painting the team into a corner.
• Designs durable execution for long-running, resumable agent runs.
• Designs the tool and authorization layer so tenant scope and permissions are enforced by the systems the agent calls.
• Owns multi-tenant isolation for agents that take write actions.
• Architects the connector framework over heterogeneous third-party security control APIs.
• Treats untrusted environment data as an attack surface; understands prompt injection and keeps model output out of the path that authorizes privileged action.
• Builds observability that makes agent behavior explainable.

Skills

Leadership

System design

Code reviews

Mentorship

Education

Bachelor's Degree in Computer Science or related field

Tools

Docker

Kubernetes

PostgreSQL

Neo4j

GraphQL

Job description

Horizon3 is seeking a Principal Software Engineer to lead the technical work for NodeZero's defensive agents, translating proven attack paths into continuous remediation. You will set direction with AI researchers and lead the engineers who build the platform underneath them.

This is a technical leadership role without direct people management. You will write production code weekly, review PRs, and partner with Product to sequence problems.