Applied AI Engineer

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3.ai

Join Horizon3 to help pioneer AI Offensive Security (AI Off Sec)—where machine learning and cybersecurity collide. We’re seeking junior engineers with a strong AI/ML foundation—especially those eager to explore reinforcement learning (RL) and modern model-tuning methods—to build intelligent agents that probe networks, discover vulnerabilities, and emulate real adversaries. You’ll help design, train, and test AI systems that continuously learn to think and act like attackers.

• 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

• Bachelor’s 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 (Num Py, pandas, scikit-learn)
• Foundational knowledge of AI/ML concepts and frameworks (PyTorch, Tensor Flow, 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

• 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, Try Hack Me , etc.) or AI/ML competitions (Kaggle)

• 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: 2–3 days a week in our Indianapolis office with flexible remote options
• Competitive Entry-Level Compensation:
  Full benefits including health, vision, and dental

• 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

• 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.

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.…