Horizon3 AI

Senior Software Engineer, Agentic Systems

US, Remote · Senior · Full-time

Sponsorship not specified$169k-$208kDetected 29 days ago

AWSLLMsAgentic AICybersecurityResearchCollaboration

About the role

NodeZero has been adopted by organizations of all sizes, from small educational institutions to government agencies and Global 100 enterprises.
It crawls and attacks real production websites the way a skilled human pentester would, finding broken access control, injection, XSS, SSRF, SSTI, and more, under a strict production-safe, no-false-positives mandate.

5+ years building production software, with strong Python.
Hands-on experience building LLM-powered applications or agents, tool use / function calling, structured outputs, multi-step orchestration, and the glue that makes it all hold together.
A track record of making LLMs reliable in production, you've wrestled nondeterminism, designed around model limitations, and shipped something that worked when it mattered.

You've shipped an autonomous agent that did real, valuable work unattended in production, and you have scar tissue from making it trustworthy.
You have hands-on experience with agent fine-tuning or RL (SFT, GRPO, reward design for tool-using agents) and a grounded view of when it's worth it versus improving the harness.

Strong instincts for prompt and context engineering, and the judgment to keep the model's job small and well-scoped.
Solid software fundamentals - testing, observability, and the discipline to keep a complex agent debuggable.
Ownership mentality, comfortable owning a critical, fast-moving subsystem end to end.
Experience with agent frameworks, and strong opinions about when not to reach for one.
Familiarity with graph data models (e.g., Neo4j) for representing application state and attack context.

We offer competitive salary, equity and benefits.
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:
$169,000 - $208,000 annually.

Our benefits include health, vision & dental insurance for you and your family, a flexible vacation policy, and generous parental leave.
All full-time roles are eligible for an equity package in the form of stock options.

Work in a collaborative environment that encourages creativity and out-of-the-box thinking.

Our commitment to diversity and inclusion means we strive to attract, develop, and retain a workforce that reflects the varied communities we serve.
equal opportunity employer - we are a community that values diversity, equity, and inclusion as fundamental principles of our culture and success.

This listing is sourced directly from Horizon3 AI's careers page and normalized into a canonical job model.