Senior Backend Engineer, Autonomous Defense
Horizon3 · Remote · US, Remote ·
COMPENSATION
€•• – ••k
Listed on the employer's job board (Ashby)
- Senior Backend Engineer
- Remote or Hybrid (US)
- Python, Go, or TypeScript
- Distributed Systems
- Equity + Health Benefits
Join the Autonomous Defense team at Horizon3 to build the infrastructure behind NodeZero, a platform for autonomous penetration testing. You will engineer the systems that allow AI agents to operate safely within customer environments, handling complex distributed workflows and strict isolation constraints.
This is a platform engineering role where you will own the agent execution runtime, tool layer, and connector framework. You will collaborate with AI researchers to transform prototypes into shippable, secure production services without directly tuning models.
What you'll do
- Build durable, resumable agent execution runtimes with checkpointing and idempotency
- Design server-side authorized tool layers with versioning and schema validation
- Develop connector frameworks for third-party security control planes like EDR and SIEM
- Implement safe-change pipelines including simulation, approval gates, and rollback
- Extend tenant isolation models to prevent cross-tenant leakage in caches and logs
- Create ETL pipelines and GraphQL APIs for agent context and remediation data
- Instrument systems with distributed tracing and per-tenant cost accounting
What you'll need
- Bachelor's degree in Computer Science, Engineering, or related field
- 7+ years of software engineering experience with modern OO or functional languages
- Experience building applications on AWS, Azure, or GCP using Docker and Kubernetes
- Expert proficiency in SQL and database interactions
- Proven track record designing distributed systems with async workflows and retries
- Experience shipping and operating production services with on-call responsibilities
Nice to have
- Experience building agentic or LLM-backed systems in production
- Familiarity with durable execution engines like Temporal or custom checkpointing
- Background in multi-tenant platforms with hard isolation and workload identity
- Knowledge of security APIs for CrowdStrike, SentinelOne, or Microsoft Defender
- Experience with PostgreSQL, Neo4j, and building GraphQL backends
- Proficiency with observability tools like Datadog, Prometheus, or Grafana
Stack
- Python
- Go
- Scala
- C++
- TypeScript
- AWS
- Azure
- GCP
- Docker
- Kubernetes
- SQL
- GraphQL
- PostgreSQL
- Neo4j
- Datadog
- Prometheus
- Grafana
How you'll work
- Remote and hybrid work models available depending on location
- Some roles may require regular presence at the Chicago office
- On-call ownership for production services is required
What you get
- Competitive base salary range of $170,000 to $235,000 annually
- Equity package in the form of stock options for full-time roles
- Health, vision, and dental insurance for employees and families
- Flexible vacation policy and generous parental leave
- Inclusive culture with career development opportunities