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Senior Backend Engineer, Autonomous Defense

Horizon3 AI· Engineering
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Remote$170k - $235kFull-timePosted 1mo ago

About the role

Senior Backend Engineer on the Autonomous Defense team building the platform that NodeZero's defensive agents run on, focusing on production-ready distributed systems, isolation, and observability to support AI researchers and secure agent actions.

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.

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.

Skills

Required:Backend development

Benefits

  • Inclusive Team: We value diversity and promote an inclusive culture where everyone can thrive.
  • Growth Opportunities: Be part of a dynamic and growing team with numerous career development opportunities.
  • Innovative Culture: Work in a collaborative environment that encourages creativity and out-of-the-box thinking.
  • Hybrid & Remote Work: We embrace a mix of remote and hybrid work models depending on role and location, including our Chicago office, where some roles require regular in-office presence.
  • Competitive Compensation: We offer competitive salary, equity and benefits. Our benefits include health, vision & dental insurance for you and your family, a flexible vacation policy, and generous parental leave.
Last updated Oct 8, 2026. Interested? Apply on the company site.

About Horizon3 AI

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Continuously assess, fix, and verify your security posture. Securing enterprises across many attack surfaces.

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