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Mercor · Finance & specialist

Performance Engineer Expert - review AI outputs in your specialty

Listed on Mercor as “Performance Engineer Expert

$100-$130/hrRemoteContractPaid in USD

What this actually is

You bring your specialist expertise to AI evaluation. The shape of the work varies but the pattern is the same: review outputs, rate quality, write prompts, flag errors. The platform title (Performance Engineer Expert) reflects the rate band and the expertise required, not the day-to-day work.

Can you do this on your visa?

F-2 / F-4 / F-5 / F-6: open. E-1 to E-7: needs concurrent-employment permit. D-2 / D-4 students: S-3 permit, 20 hr/week cap. D-10 / D-8: case by case.

Korean tax on USD income

First 5 years in Korea: foreign-source income only taxed if remitted into Korea. After year 5: worldwide income. Full tax guide.

Original posting from Mercor

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.

1\. 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 MLOps 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.

2\. 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.

3\. 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 30 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.

Quoted from Mercor’s public listing on 2026-06-02. We don’t edit platform copy; honest framing is in the title and the “what this actually is” block above.