Senior Backend Engineer, Autonomous Defense Platform

Openkrill; United States; Hybrid; USD 170,000 - 235,000; Full time

Benefits offered by this job

Inclusive team

Growth opportunities

Innovative culture

Hybrid & remote work

Competitive compensation

Job summary

Horizon3 is hiring a Senior Backend Engineer to build and run the NodeZero platform, delivering autonomous defense capabilities for thousands of tenants. You will own the runtime, tool layer, and orchestration, ensuring safe, auditable actions across production environments.

You’ll collaborate with AI researchers to translate prototypes into production-ready systems with strong isolation, observability, and scalable performance. Hybrid/remote role with some in-office requirements.

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, using container technologies such as Docker and Kubernetes.
• 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

• Build and own the agent execution runtime: durable, resumable, long-running workflows with checkpointing, idempotent steps, cancellation, and timeouts at both the step and run level.
• Design and implement the tool layer that agents act through — a registry with versioning, schema validation, per-tenant enablement, and authorization enforced server-side rather than by the model.
• Build the connector framework for third-party security control planes (EDR, firewall, identity, SIEM, cloud IAM).
• Implement the safe-change pipeline: dry-run and simulation, blast-radius classification, approval gates for high-impact actions, staged rollout, rollback, and an immutable per-tenant audit trail.
• Extend NodeZero's tenant isolation model to agents that take write actions, covering execution boundaries, egress control, quotas, and cross-tenant leakage in caches, indexes, and logs.
• Develop core product features in ETL and GraphQL to support data processing and retrieval for agent context, run history, and remediation state.
• Build the ETL pipelines that turn pentest and remediation outcomes into the datasets our researchers train and evaluate against.
• Instrument everything. Distributed tracing across an agent run, cost and token accounting per tenant, and the tooling to answer "why did the agent do that" without guessing.
• Partner with AI researchers, attack engineers, and product to take capabilities from prototype to production, and feed platform constraints back into research direction early rather than late.

Skills

Python

Go

Scala

C++

TypeScript

Education

Bachelor's Degree in Computer Science, Computer Engineering or related field

Tools

Docker

Kubernetes

Temporal

GraphQL

PostgreSQL

Neo4j

Datadog

Prometheus

Grafana

Job description

Horizon3 is hiring a Senior Backend Engineer to build and run the NodeZero platform, delivering autonomous defense capabilities for thousands of tenants. You will own the runtime, tool layer, and orchestration, ensuring safe, auditable actions across production environments.

You’ll collaborate with AI researchers to translate prototypes into production-ready systems with strong isolation, observability, and scalable performance. Hybrid/remote role with some in-office requirements.