Horizon3.ai

Staff Software Engineer, Defensive Agent

Horizon3.ai$229K — $270K *
US-AnywhereRemote in United States
Information Technology
5 - 7 years of experience
Job Overview by Ladders

Qualifications

  • Bachelor's degree in Computer Science, Computer Engineering, or related field.
  • 7+ years of professional software engineering experience in modern languages (Python, Go, Scala, C++, TypeScript, etc.).
  • Proficient in building applications on cloud platforms (AWS, Azure, GCP) and using container technologies (Docker, Kubernetes).
  • Deep experience with production-level agentic or LLM-backed systems, along with an awareness of their limitations.
  • Expert proficiency in SQL and designing distributed systems in production.

Responsibilities

  • Own the technical vision and guide the team through all phases of development, from ideation to production.
  • Contribute production-level code regularly in a modern backend language within a service-oriented infrastructure.
  • Elevate the quality of technical outputs through leading by example during design reviews and code quality checks.
  • Mentor engineers and develop frameworks for high-quality work.
  • Ensure accountability by focusing on outcomes and proactively identifying risks and tradeoffs.
  • Act as a liaison between AI research and platform engineering to align research direction with platform constraints.
  • Translate ambiguous product goals into actionable technical roadmaps.

Benefits

  • Inclusive team culture that values diversity and fosters inclusion.
  • Career growth opportunities with a dynamic and expanding team.
  • Collaborative and innovative work environment.
  • Hybrid and remote work flexibility based on role and location.
  • Comprehensive health, vision, and dental insurance for employees and their families.
Full Job Description
What You'll Do

We are hiring a Staff Software Engineer to lead the technical work for NodeZero's defensive agents: the systems that translate proven attack paths into continuous actionable remediation.

You'll set direction alongside our AI researchers, who define what the agents should reason about, and lead the engineers who build the platform underneath them. Over time this role owns the technical strategy for how autonomous remediation becomes a core NodeZero product capability rather than a set of recommendations in a report.

This is a technical leadership role without direct people management. You lead through architecture, code, design review, and mentorship, not through performance reviews and headcount. It is also not a pure architect role. You will write production code every week, review PRs from the engineers you lead, and partner closely with Product to sequence the right problems in the right order. You will be the person who both draws the system diagram on the whiteboard and commits the first slice of it to main.

Responsibilities
Leadership & Team Development
  • Owns the end-to-end technical vision for the workstream and rallies the team around it - from blank doc through shipping, iterating, and deprecating.
  • Production code contributions at Lead/Staff level in a modern backend language (Python, Go, Rust, or similar) in a service-oriented environment.
  • Sets and raises the technical bar (design reviews, code quality, operational discipline) by example rather than by mandate.
  • Mentors and enhances the engineers around them; builds the frameworks and architecture for others to do the best work of their careers.
  • Holds the team accountable to outcomes rather than activity; surfaces risks and tradeoffs early and in writing.
  • Serves as the durable technical interface between AI research and platform engineering, so research direction accounts for platform constraints early rather than at handoff.
Product-Minded Technical Leadership
  • Translates ambiguous product goals into concrete technical roadmaps.
  • Makes build vs. buy vs. integrate calls with business context, not just engineering preference - including which model providers, orchestration frameworks, and control-plane integrations we own versus adopt.
  • Partners closely with PM - comfortable in PRD reviews, not just sprint planning.
  • Sequences an MVP without painting the team into a corner.
Agentic Systems & Platform Expertise
  • Designs durable execution for long-running, resumable agent runs.
  • Designs the tool and authorization layer so tenant scope and permissions are enforced by the systems the agent calls.
  • Owns multi-tenant isolation for agents that take write actions.
  • Architects the connector framework over heterogeneous third-party security control APIs.
  • Treats untrusted environment data as an attack surface; understands prompt injection and keeps model output out of the path that authorizes privileged action.
  • Builds observability that makes agent behavior explainable..


Required Education / Experience
  • 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.
  • Deep experience with agentic or LLM-backed systems in production with a clear-eyed view of where they fail and how to contain it.
  • 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.


What Sets You Apart
  • Experience with a durable execution (such as Temporal) or workflow engine or having built equivalent checkpointing yourself.
  • 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 - EDR (CrowdStrike, SentinelOne, Microsoft Defender), firewalls, SIEM, cloud IAM.
  • Experience with database architectures including relational (PostgreSQL) and graph (Neo4j), and experience building GraphQL backends.


Perks of Horizon3
  • 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.


Compensation and Values

At Horizon3, we believe that our people are our greatest asset, and our compensation philosophy reflects this core value. We are committed to fostering an environment where all employees feel valued, respected, and rewarded for their contributions. Our compensation structure is designed to be fair, competitive, and transparent, ensuring that every team member is recognized and compensated equitably across roles, levels, and locations.

In accordance with various State's transparency regulations, we provide the following salary range information for this position:
  • Base salary range: $229,000-$270,000 annually. The exact salary will be determined based on the selected candidate's location, qualifications, experience, and relevant skills.
  • Additional compensation: All full-time roles are eligible for an equity package in the form of stock options.


Other Duties

Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee. Duties, responsibilities, and activities may change at any time with or without notice.

About Horizon3.ai

Horizon3.ai is a California-based software company that provides artificial intelligence (AI) solutions for businesses. The company was founded in 2018 and is headquartered in Long Beach, California. Horizon3.ai offers a range of AI-powered products, including chatbots, virtual assistants, and predictive analytics tools. The company's solutions are designed to help businesses automate their operations, improve customer engagement, and gain insights from their data. Horizon3.ai serves clients in a variety of industries, including healthcare, finance, and retail.
Learn more about Horizon3.ai
Size
50 employees
Industry
Net Income
-$100,000
Founded
2018
5 Year Trend
+50%
Revenue
$500,000

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