Performance Engineer (C++, Python, Rust)

Performance Engineer (C++, Python, Rust)

$70-$110 per hour

Hourly contract United States

Join a leading AI lab's cutting-edge GenAI team to be at the core of the AI revolution, where your expertise fuels the development of the most advanced Large Language Models.

Overview

We're seeking talented Performance Engineers with deep expertise in low-level systems optimization — specifically C++, Python, and Rust — to bring hands-on technical excellence and elevate the quality of our AI training and inference infrastructure data. This role involves AI model training and evaluation work, including writing and assessing performance-engineering tasks and solutions to generate high-quality training data for frontier AI systems.

This is a W-2 employment position with Cincinnatus LLC, with the opportunity to be placed at a leading AI Lab as part of their extended workforce. This is a 40-hour full-time engagement, with no conflicts/no other engagements.

Key Responsibilities

• Guide research and engineering teams to close knowledge gaps and improve AI model performance in systems-level optimization, compiler engineering, and runtime performance topics.
• Design challenging, domain-relevant tasks across multiple specializations, and write accurate and well-structured solutions to performance engineering problems.
• Evaluate performance engineering tasks and solutions and provide clear, written technical feedback.
• Develop guidelines and detailed rubrics/evaluation frameworks to assess systems design quality across AI workloads.
• Collaborate with other subject matter experts to ensure consistency and accuracy in training data.

Core Qualifications

• 2+ years of dedicated professional experience in performance engineering, systems programming, or low-level optimization.
• Deep hands-on expertise in at least one of the following: C++, Python, or Rust — with working familiarity across the others being a strong plus.
• Demonstrable track record of measurable performance improvements on production systems (e.g., latency reduction, throughput gains, memory footprint optimization).
• Demonstrable career progression.
• Ability to engage reliably for at least 40 hours/week during weekdays.
• Strong written communication skills and the ability to explain complex technical decisions clearly.

About Cincinnatus LLC: Cincinnatus LLC is an enterprise staffing company that partners with leading technology companies to source and employ highly skilled professionals for contingent and contract-based opportunities. Cincinnatus serves as the employer of record for these engagements, providing W-2 employment, payroll, benefits, and compliance, while placing employees directly within client teams to work on high-impact initiatives.

Equal Employment Opportunity: Cincinnatus is proud to be an Equal Employment Opportunity employer. We do not discriminate based upon race, religion, color, national origin, sex (including pregnancy, childbirth, reproductive health decisions, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, genetic information, political views or activity, or any other legally protected characteristic.

We consider all qualified applicants without regard to legally protected characteristics and provide reasonable accommodations upon request.

Contract and Payment Terms

• You will be engaged as an independent contractor.
• This is a fully remote role that can be completed on your own schedule.
• Projects can be extended, shortened, or concluded early depending on needs and performance.
• Your work at Mercor will not involve access to confidential or proprietary information from any employer, client, or institution.
• Payments are weekly on Stripe or Wise based on services rendered.
• Please note: We are unable to support H1-B or STEM OPT candidates at this time.

About Mercor

Mercor partners with leading AI labs and enterprises to train frontier models using human expertise. You will work on projects that focus on training and enhancing AI systems. You will be paid competitively, collaborate with leading researchers, and help shape the next generation of AI systems in your area of expertise.

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