Principal Software Engineer, Horizon3
Autonomous Defense
$255-300k
+ All full-time roles are eligible for an equity package in the form of stock options
Autonomous security solutions
Open for applications
Autonomous security solutions
201-500 employees
Open for applications
$255-300k
+ All full-time roles are eligible for an equity package in the form of stock options
201-500 employees
Company mission
To help find and fix attack vectors before attackers can exploit them.
Role
Who you are
- Bachelor's Degree in Computer Science, Computer Engineering or related field
- 10+ 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
Desirable
- 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
What the job involves
- We are hiring a Principle 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
- 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
- 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
- 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
Our take
In an era marked by escalating cyber threats and data breaches, safeguarding digital assets has become a high priority across all industries. Amid this landscape, Horizon3.ai stands out as an autonomous security solution by addressing the critical need for robust cybersecurity.
At the heart of Horizon3.ai's mission is NodeZero™, a platform designed to elevate proactive security measures. Using this, customers can verify their security posture and identify potential vulnerabilities through self-service. This proactive approach to cybersecurity effectively thwarts potential exploits and ensures the integrity of their digital infrastructure.
With 2025 funding in hand, the company is poised to further its ambition to develop into an industry-leading cybersecurity company. The infusion of funds will be channelled towards expanding its partner network, refining its offerings and entering the US government market. Horizon3 aims to establish itself as a pivotal player in the evolving autonomous security landscape, a highly lucrative market valued at $80 billion.
Kirsty
Company Specialist at Welcome to the Jungle
Insights
-8% employee growth in 12 months
Company
Funding (last 2 of 6 rounds)
Jun 2025
$100m
SERIES D
Aug 2023
$40m
SERIES C
Total funding: $187m
Company benefits
- Growth Opportunities: Be part of a dynamic and growing team with numerous career advancement opportunities
- Innovation-Driven Culture: Work in a collaborative environment that encourages creativity and out-of-the-box thinking
- Flexible Work Environment: Enjoy the convenience and work-life balance that comes with remote work
- Inclusive and Diverse Team: We value diversity and promote an inclusive culture where everyone can thrive
Company HQ
SoMa, San Francisco, CA
Leadership
Snehal Antani
(Co-Founder & CEO)Graduated from the Rensselaer Polytechnic Institute with an MS in Computer Science. Previously worked at IBM as a Lead Architect, at GE Capital as the CIO of Distribution Finance and Splunk as the SVP & GM of Business Analytics & IoT.
Anthony Pillitiere
(Co-Founder)Graduated from the University of Maryland with a Bachelor's Degree in Computer Systems Networking and Telecommunications. Previously worked at the United States Air Force in multiple roles, including Deputy Chief Technology Officer.
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