Senior Software Engineer

Responsibilities

• Design, build, and refine reinforcement learning (RL) tasks, owning the full lifecycle from ideation through grading and failure analysis.
• Tackle complex environments involving multi-step workflows, realistic stakeholder interactions, and large codebases with technical debt.
• Utilize coding agents heavily to direct workflows, evaluate outputs, and identify subtle failure modes.
• Contribute to shared infrastructure and tooling.
• Provide mentorship to newer team members as needed.

Requirements

• Deep software engineering expertise across multiple domains (e.g., infrastructure, distributed systems, performance, or security).
• Proficiency in Python.
• Extensive experience working with coding agents.
• Ability to work independently on complex, ambiguous problems.
• Strong intuition for AI model behavior and the ability to distinguish genuine capability gaps from grader issues.

Preferred Qualifications

• Experience designing tasks that target deep, subtle failure modes in software engineering.
• No prior ML or AI experience is required, but a strong interest in the field is essential.

Benefits

• $400,000 base salary.
• Equity and performance bonuses.
• Health, dental, vision, and life insurance.

About the Company

Mechanize is a ~20 person team based in San Francisco. We build reinforcement learning environments used by frontier AI labs to train and evaluate coding models. Our mission is to help AI models move beyond narrow coding tasks to master the complex, judgment-heavy aspects of software engineering. We are backed by prominent industry leaders including Patrick Collison, Nat Friedman, and Jeff Dean.