Horizon3.ai

4 weeks ago

Senior Software Engineer, Agentic Systems

✓ Verified Job

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

Source: Company careers pageValidated by: Fursa AI

Last checked: 12 hours agoStatus: Live

Job Summary

Develop and evolve autonomous agent capabilities to power a production-ready, LLM-driven web application pentester. Build the agent harness, tooling, evaluation infrastructure, and production inference, ensuring reliability, safety, and scalable performance in a security-focused autonomous system.

Location: United States

Workplace: Remote

Employment Type: Full time

Job Function: Software Engineering

Key Responsibilities

•Build and evolve the agent harness and orchestration that turns an LLM into a reliable autonomous pentester, the loop that reasons over an application, forms attack hypotheses, acts, and verifies results.
•Design the tools and tool-shaped feedback the agent uses to probe and exploit, and the structured-output and validation layers that keep it reliable.
•Translate the team's offensive expertise into repeatable agent capabilities, encoding how attackers think into a system the agent can perform consistently.
•Own and grow our evaluation infrastructure: benchmark suites, failure-mode taxonomy, regression detection, and monitoring to track improvements.
•Manage LLM inference in production: model selection, prompt/context engineering, and cost/latency control (AWS Bedrock).

Pay and Benefits

Salary: USD 169,000 - 208,000 annually

Equity and Bonus:Equity

Perks:Health InsuranceVisionDentalEquityRemote WorkParental LeavePaid Leave

Key Requirements

•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.
•A track record of making LLMs reliable in production, handling nondeterminism and modeling limitations.
•Real experience with evaluation: built or owned harness to measure model/agent improvement.
•Strong instincts for prompt and context engineering, with the ability to keep the model's job small and well-scoped.

Experience:5+ years

Skills:PythonLLMPrompt engineeringTestingObservabilityCost controlArchitectureEngineering reliability

Languages:English

Tech Stack:PythonAWS BedrockLLMAgent frameworksPrompt engineeringTestingObservability

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: 4.9

Website LinkedIn Glassdoor

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Horizon3.ai

4 weeks ago

Senior Software Engineer, Agentic Systems

✓ Verified Job

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

Source: Company careers pageValidated by: Fursa AI

Last checked: 12 hours agoStatus: Live

Job Summary

Location: United States

Workplace: Remote

Employment Type: Full time

Job Function: Software Engineering

Key Responsibilities

•Build and evolve the agent harness and orchestration that turns an LLM into a reliable autonomous pentester, the loop that reasons over an application, forms attack hypotheses, acts, and verifies results.
•Design the tools and tool-shaped feedback the agent uses to probe and exploit, and the structured-output and validation layers that keep it reliable.
•Translate the team's offensive expertise into repeatable agent capabilities, encoding how attackers think into a system the agent can perform consistently.
•Own and grow our evaluation infrastructure: benchmark suites, failure-mode taxonomy, regression detection, and monitoring to track improvements.
•Manage LLM inference in production: model selection, prompt/context engineering, and cost/latency control (AWS Bedrock).

Pay and Benefits

Salary: USD 169,000 - 208,000 annually

Equity and Bonus:Equity

Perks:Health InsuranceVisionDentalEquityRemote WorkParental LeavePaid Leave

Key Requirements

•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.
•A track record of making LLMs reliable in production, handling nondeterminism and modeling limitations.
•Real experience with evaluation: built or owned harness to measure model/agent improvement.
•Strong instincts for prompt and context engineering, with the ability to keep the model's job small and well-scoped.

Experience:5+ years

Skills:PythonLLMPrompt engineeringTestingObservabilityCost controlArchitectureEngineering reliability

Languages:English

Tech Stack:PythonAWS BedrockLLMAgent frameworksPrompt engineeringTestingObservability

Company Brief

Horizon3.ai

Industry: Cybersecurity

Company Size: Large (251 to 1,000 employees)

Growth: Scaleup

Funding: Series D

Headquarters: San Francisco, United States

Founded: 2019

Glassdoor: 4.9

Website LinkedIn Glassdoor