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Applied AI Engineer 1
role at
Horizon3.ai
Overview
Join Horizon3 to help pioneer
AI Offensive Security (AI OffSec) where machine learning and cybersecurity collide. Were seeking junior engineers with a strong AI/ML foundationespecially those eager to explore
reinforcement learning (RL)
and modern model-tuning methodsto build intelligent agents that probe networks, discover vulnerabilities, and emulate real adversaries. Youll help design, train, and test AI systems that continuously learn to think and act like attackers.
Essential Functions
Develop AI systems for vulnerability detection and autonomous security testing
Design and train reinforcement-learning and fine-tuning workflows (e.g., PPO, LoRA/QLoRA) to improve automated security agents
Automate security testing pipelines with Python and modern ML frameworks
Contribute to feature development from concept through deployment, including model evaluation and experiment tracking
Identify and document vulnerabilities in AI-native applications and LLM workflows
Research emerging AI security threats, prompt-injection tactics, and adversarial ML
Document findings and help build a technical knowledge base
Core Competencies / Requirements
Bachelors degree in Computer Science, Machine Learning, Artificial Intelligence, Data Science, Software Engineering, Mathematics, Statistics, or a related field
Strong Python skills and comfort with data-science libraries (NumPy, pandas, scikit-learn)
Foundational knowledge of AI/ML concepts and frameworks (PyTorch, TensorFlow, or JAX)
Exposure to reinforcement learning or similar methods (deep Q-learning, PPO) through coursework, labs, or projects
Understanding of model training life cycle: data prep, feature engineering, and evaluation
Experience with Linux environments and Git version control
Interest in cybersecurity and ethical hacking
Strong problem-solving and clear communication skills
Must be located in or willing to relocate to the Indianapolis metropolitan area
Desired / Nice to Have
Hands-on projects fine-tuning LLMs or training LoRA/QLoRA adapters
Experience with vector databases or retrieval-augmented generation (RAG)
Familiarity with AI security topics (model inversion, adversarial attacks)
Internship or academic work in reinforcement learning or autonomous agents
Contributions to open-source RL or adversarial-ML projects
Experience with Docker and containerized ML ops (Docker/Kubernetes)
Experience with cloud platforms (AWS, Azure, or GCP)
Security certifications (Security+, etc.) or active pursuit of them
Participation in CTF platforms (Hack The Box, TryHackMe, etc.) or AI/ML competitions (Kaggle)
What We Offer
Deep Mentorship: Work side-by-side with experienced engineers to master real-world AI security pipelines
Career Growth: Opportunity to become a core technical leader as our AI offensive security stack expands
Hybrid Flexibility: 23 days a week in our Indianapolis office with flexible remote options
Competitive Entry-Level Compensation: Full benefits including health, vision, and dental
Ideal Mindset
Eager to learn and grow in both AI and cybersecurity
Self-motivated, detail-oriented, and collaborative
Curious hacker mindset with a drive to experiment and break things safely
Perks of Horizon3.ai
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.
Remote Work: We are a 100% remote company. Enjoy the convenience and work-life balance that comes with remote work.
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.
Additional compensation: All full-time roles are eligible for an equity package in the form of stock options.
You Belong Here
Horizon3 is not just an equal opportunity employer - we are a community that values diversity, equity, and inclusion as fundamental principles of our culture and success. We are dedicated to fostering a workplace where everyone feels welcome and respected, regardless of race, color, religion, sex, national origin, age, disability, veteran status, sexual orientation, gender identity or expression, genetic information, marital status, or any other legally protected status by law. We welcome candidates from all backgrounds and experiences, and we encourage all qualified individuals to apply. Come be a part of Horizon3, where your unique contributions are recognized, and your potential is limitless.
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.
Location: Indianapolis, IN
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