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Mercor · Software & coding

Scientific / ML Engineer

Listed on Mercor as “Scientific / ML Engineer”

$90-$140/hrRemoteContractPaid in USD
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How this rate compares

This listing

$90–$140 per hour

Typical in Software & coding

$70–$120 per hour

Within the typical range

Typical: the middle of the lowest and highest rates posted by 36 listings in this category on Seoulstart, in US dollars.

What this actually is

You review AI-generated code, rank model outputs against each other, write prompts that test edge cases, and provide expert feedback that gets used to train coding models. Not shipping production software. The platform title (Scientific / ML Engineer) reflects the rate band and the expertise required, not the day-to-day work.

How Mercor picks people

  1. Upload your CV and answer the role's written questions.
  2. Do a video interview with Mercor's AI interviewer. Most take about 20 minutes, in English unless the role says otherwise.
  3. Some roles add a skills test. A test you pass once counts for similar roles.
  4. The project team reviews your results and sends offers to the people it picks.

Before you start

  • Take Mercor's free practice interview first. It does not count toward any application.
  • Use Chrome on a computer with a camera and microphone, in a quiet room.
  • You can retake an official interview up to 3 times, but hiring teams see how many times you retook it.

Not every applicant gets an offer. Prepare well for the interview.

How to prepare for the Mercor interview

Source: Mercor's help pages. talent.docs.mercor.com

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

Join a leading AI lab's cutting-edge GenAI team and help build foundational AI models from the ground up. We're seeking talented Machine Learning Engineers and Scientific Computing experts with hands-on expertise in machine learning, deep learning frameworks and scientific computing to bring hands-on technical and research excellence and elevate the quality of our AI training data.

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.

2\. Key Responsibilities

  • Guide research and engineering teams to close knowledge gaps and improve AI model performance in machine learning and scientific computing, model training and evaluation, and numerical and scientific software topics.
  • Design challenging, domain-relevant tasks, and write accurate and well-structured solutions to machine learning and scientific computing problems.
  • Evaluate machine learning and scientific computing tasks and solutions and provide clear, written technical feedback.
  • Design and evaluate technical tasks covering model training, experiment design, data pipelines and scientific simulations, with runnable reference solutions.
  • Develop rubrics to assess the methodological soundness, correctness and reproducibility of ML and scientific work.
  • Collaborate with other subject matter experts to ensure consistency and accuracy in training data.

3\. Core Qualifications

  • 4+ years of dedicated professional or research experience in machine learning, data science or scientific computing at a recognized, top-tier organization or research university (an MS or PhD in a quantitative field counts toward this).
  • Production or research experience with PyTorch, JAX or TensorFlow, and strong Python (NumPy, pandas, scikit-learn).
  • Publications, open-source contributions or shipped ML systems are a strong plus.
  • Demonstrable career progression.
  • Ability to engage reliably for at least 20 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 2026-11-13. We don't edit platform copy; honest framing is in the title and the “what this actually is” block above.

Mercor pays Seoulstart a fee if it hires you through this link. Your pay is the same.