Machine Learning Engineer

What you'll do

You teach models machine learning by writing the questions and checking the answers. You design ML and LLM engineering tasks (data pipelines, training and evaluation code, experiment design) with reference solutions, evaluate AI-generated training, evaluation and data-processing code for correctness and efficiency, and write reference answers and rubrics at professional depth. A distinctive part of the job is methodology review: spotting data leakage, poor metric choice, weak baselines and reproducibility problems in what a model proposes. You also compare outputs and document recurring errors in the model's ML reasoning.

This has the highest floor among Rex.Zone's software roles ($75) with a top of $150, and it leans on methodology judgment more than on writing production code. Work is remote contract with calibration and review sessions.

Who fits

• A degree in computer science, statistics or a related field, or equivalent experience
• 3+ years of machine learning engineering or applied ML
• Python with PyTorch or TensorFlow, and solid grounding in model training, evaluation and deployment
• Experience building data pipelines and tracking experiments
• Fluent written English

Preferred, not required: LLM fine-tuning or evaluation experience, published work or strong competition results, experience with distributed training or inference optimisation, and prior AI-training or annotation work.

What it pays

The listing states $75–150 an hour, the highest floor among Rex.Zone's software roles.

Rex.Zone's listing states USD $75–150 per hour, "adjusted by country of residence". The ad does not say how the adjustment works, so the top of the range may not apply everywhere, and where an offer lands in the range is not published. Payment terms are not published on the listing.

Worth knowing

Good:

• Open worldwide, with no country restriction stated
• The highest floor ($75) and a $150 ceiling
• Methodology review uses research judgment, not only coding speed

Less good:

• Pay is adjusted by country of residence and the ad does not explain how
• Verified-users-only applications and an entry exam come before any paid work
• The ad states no hours or volume, so how much work you get is unknown
• Contractor agreement terms on ownership and licence are still marked as to be confirmed by Rex Legal
• Submissions cannot include confidential or proprietary material from an employer or client

About this listing

Posted on the Rex.Zone expert portal on 1 October 2026 and read from the signed-in portal on 29 October 2026. The requirements above are the ad's own; it lists no skills tags. Rex.Zone does not publish payment methods or payout timing, and the listing does not say how pay is adjusted by country. The portal marks applications as open to verified users only, and most roles sit behind an entry exam. See Rex.Zone.