Senior Backend Engineer, Autonomous Defense

The role

You will build the platform that NodeZero's defensive agents run on. This involves owning the runtime, tool layer, orchestration, connector framework, and observability.

What you will do

• Build and own the agent execution runtime
• Design and implement the tool layer for agents
• Build the connector framework for third-party security control planes
• Implement the safe-change pipeline
• Extend NodeZero's tenant isolation model
• Develop core product features in ETL and GraphQL
• Build ETL pipelines for researcher datasets
• Instrument distributed tracing and cost accounting
• Partner with AI researchers, attack engineers, and product

Required qualifications

• Bachelor's Degree in Computer Science, Computer Engineering or related field
• 7+ 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
• Experience using container technologies such as Docker and Kubernetes
• 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 building agentic or LLM-backed systems in production
• Experience with a durable execution (such as Temporal) or workflow engine
• 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
• Experience with database architectures including relational (PostgreSQL) and graph (Neo4j)
• Experience building GraphQL backends
• Experience with observability tooling (Datadog, Prometheus, Grafana) and distributed tracing
• Awareness of prompt injection and untrusted-input handling

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. The team is a fusion of former U.S. Special Operations cyber operators, startup engineers, and formerly frustrated cybersecurity practitioners.