Senior Backend Engineer, Defensive Agent

Horizon3.ai
United States
Workplace: RemoteFull timeUSD 199,000 - 235,000 annuallyFunction: Software EngineeringEducation: bachelorsSkills: ["Collaboration","Ownership","Results","Respect"]

Build the platform powering defensive agents for the NodeZero system, turning AI researcher intents into safe, production-ready distributed workflows. Own the runtime, tool layer, orchestration, connectors, and observability used across thousands of customer tenants. Design simulation and safe-change pipelines with approval gates and immutable audit trails, extend strict tenant isolation for write actions, and deliver ETL/GraphQL backends that support agent context, history, and remediation.

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FursaFursa
Horizon3.ai
Horizon3.ai
2 days ago

Senior Backend Engineer, Defensive Agent

✓ Verified Job

Canonical indexed version, validated from employer's careers page.

Source: Company careers pageValidated by: Fursa AI
Last checked: 14 hours agoStatus: Live

Job Summary

Build the platform powering defensive agents for the NodeZero system, turning AI researcher intents into safe, production-ready distributed workflows. Own the runtime, tool layer, orchestration, connectors, and observability used across thousands of customer tenants. Design simulation and safe-change pipelines with approval gates and immutable audit trails, extend strict tenant isolation for write actions, and deliver ETL/GraphQL backends that support agent context, history, and remediation.
Location: United States
Workplace: Remote
Employment Type: Full time
Job Function: Software Engineering
Seniority: Mid level

Key Responsibilities

  • •Build and own the defensive agent execution runtime with durable, resumable long-running workflows, checkpointing, idempotent steps, and step/run-level cancellation and timeouts.
  • •Design and implement the tool layer agents use, including versioned registries, schema validation, per-tenant enablement, and server-side authorization.
  • •Build a connector framework for third-party security control planes such as EDR, firewall, identity, SIEM, and cloud IAM.
  • •Implement a safe-change pipeline with simulation/dry-runs, blast-radius classification, approval gates for high-impact actions, staged rollout, rollback, and an immutable per-tenant audit trail.
  • •Develop ETL and GraphQL product features and build ETL pipelines that turn pentest/remediation outcomes into datasets for researchers, while instrumenting tracing and accounting for debuggability.

Pay and Benefits

Salary: USD 199,000 - 235,000 annually
Equity and Bonus:Equity
Perks:Health InsuranceVisionDentalRemote WorkParental LeaveEquity

Key Requirements

  • •Bachelor’s degree in Computer Science, Computer Engineering, or related field.
  • •7+ years professional software engineering experience using modern object-oriented or functional languages (e.g., Python, Go, Scala, C++, TypeScript).
  • •Experience building cloud applications on AWS, Azure, or GCP and using Docker and Kubernetes.
  • •Expert proficiency in SQL and demonstrated production experience designing/distributing systems with asynchronous workflows, queues, retries, idempotency, and partial failure.
  • •Track record shipping and operating production services with on-call ownership.
Experience:CybersecuritySaaS
Education:Bachelor's
Skills:CollaborationOwnershipResultsRespect
Tech Stack:PythonGoScalaC++TypeScriptAWSAzureGCPDockerKubernetesSQLETLGraphQLPostgreSQLNeo4jTemporalDatadogPrometheusGrafanaDistributed tracing

Company Brief

Horizon3.ai
Builds NodeZero®, an autonomous penetration-testing platform that continuously finds, prioritizes, and verifies exploitable vulnerabilities across on-premises, cloud, and hybrid environments to help organizations reduce security risk.
Industry: Cybersecurity
Company Size: Large (251 to 1,000 employees)
Growth: Scaleup
Funding: Series D
Headquarters: San Francisco, United States
Founded: 2019
Glassdoor
Glassdoor: 4.9
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