Founding AI Engineer (Remote) - RL Security & Apps

Harden; San Francisco (CA); Hybrid; USD 120,000 - 250,000; Full time

Job summary

Harden is seeking a founding AI Engineer to design and ship RL-driven optimization loops for security-hardening of AI-generated apps. You’ll work across research, ML engineering, and security engineering to production systems inside CI/CD and BYOC environments.

You will build backend services, train reward models, and scale distributed training for AI-assisted code analysis. A hands-on, collaborative engineer with strong Python and systems skills will thrive in our fast-moving startup.

Qualifications

• Proficient in Python; TypeScript/Go/Rust bonus for systems.
• Strong LLM systems intuition with tool-use and telemetry.
• Have shipped production ML or security-enabled systems.
• Experience designing experiments and evals for ML models.
• Fluent data pipelines, logging, and reproducible workflows.
• Excellent communication in fast, ambiguous environments.
• 2+ years building ML systems.
• Familiar with authentication, authorization, secrets, sandboxing, prompt injection.

Responsibilities

• Design RL loops for multi-step, tool-using agents for security hardening.
• Build backend services for training, evals, and policy updates.
• Train reward models; run A/B tests with security signals.
• Scale distributed training/serving for AI-assisted code analysis and deployments.
• Turn research papers into maintainable code in Harden.
• Collaborate with product and customers to define measurable rewards.
• Combine LLM reasoning with deterministic SAST/SCA and runtime telemetry.

Skills

Python

TypeScript

Go

Rust

LLM systems

Production systems

Experimentation

Data pipelines

Communication

ML systems

Security concepts

Job description

Harden is seeking a founding AI Engineer to design and ship RL-driven optimization loops for security-hardening of AI-generated apps. You’ll work across research, ML engineering, and security engineering to production systems inside CI/CD and BYOC environments.

You will build backend services, train reward models, and scale distributed training for AI-assisted code analysis. A hands-on, collaborative engineer with strong Python and systems skills will thrive in our fast-moving startup.