JavaScript / TypeScript AI Evaluation Developer

About OpenTrain

OpenTrain is the #1 platform for finding and building careers in AI training and data labeling. We help people start and grow freelance careers teaching AI by centralizing projects, tracking experience, and building a portable portfolio of model-evaluation and annotation work.

OpenTrain AI is the hiring and contracting organization for this role. Creating an OpenTrain account is free and is how you will apply and manage your work.

Why AI training matters

AI training (also called data labeling or human feedback work) is the human side of building intelligent systems. Developers and evaluators create the examples and judgments modern models learn from—everything from response ranking to supervised fine-tuning and RLHF.

This field is highly flexible and remote-friendly, making it a great fit for freelancers who want part-time, impactful technical work that directly shapes model behavior.

The role

We are hiring a JavaScript/TypeScript Full-Stack Developer for freelance AI work focused on model training, evaluation, and response refinement. This is an intermediate-level contractor role expected to run at 20+ hours per week and is open to contributors worldwide who speak strong English.

Work blends hands-on development with model benchmarking, response ranking, dataset creation for SFT, and participation in RLHF workflows. You will write evaluation rationales and collaborate with cross-functional teams to improve models and product quality.

• Engagement: Contractor, part-time (20+ hours/week)
• Location: Remote, worldwide
• Language: English (strong spoken and written required)

What you'll do

You will write and maintain code that supports training and evaluating AI models, perform structured evaluations, produce clear rationales for judgments, and help create high-quality datasets for supervised fine-tuning and RLHF.

Expect to collaborate on code and documentation reviews and to partner with other contributors to analyze benchmark results and refine reward models and evaluation criteria.

• Design, develop, and maintain code used to train and optimize AI models
• Benchmark model performance and analyze results for improvement
• Evaluate and rank model responses and write clear rationales
• Support dataset creation for SFT and assist RLHF workflows
• Review code and documentation; provide constructive technical feedback

Requirements

Candidates must have strong JavaScript or TypeScript experience and be comfortable building modular, scalable web apps. You should be able to write readable, reusable, and maintainable code and participate in code review processes.

A degree in Engineering, Computer Science, or equivalent experience is expected. Familiarity with testing, Docker, and software QA practices is a plus.

• Strong JavaScript or TypeScript development experience
• Experience with ES6 and at least one: Node.js, React, Nest.js, Angular, or Vue
• Ability to write readable, reusable, maintainable code and perform code reviews
• Comfort with testing, test planning, and Docker (preferred)
• Strong spoken and written English communication skills
• Bachelor’s or master’s degree in Engineering/Computer Science or equivalent experience

Helpful background

Prior exposure to AI model evaluations, response ranking, supervised fine-tuning (SFT), or reinforcement learning with human feedback (RLHF) will help you move faster in this role. Experience writing technical rationales for evaluation decisions is also valuable.

This role centers on TEXT data and label types RLHF, EVALUATION_RATING, and FINE_TUNING, so familiarity with those workflows is beneficial.

• Experience with model evaluations, SFT, RLHF, or response ranking
• Experience producing clear technical rationales for review decisions
• Comfort working with text-centric datasets and evaluation labels

How it works & how to apply

OpenTrain AI hires and manages contracts for this role. Compensation details are not specified in this listing and will be provided during the application process.

To apply, create a free OpenTrain account, complete your profile with relevant JavaScript/TypeScript and AI evaluation experience, and submit your application through the OpenTrain platform.

• Employment type: Contractor, part-time
• Time commitment: 20+ hours per week
• Data type: TEXT; label types: RLHF, EVALUATION_RATING, FINE_TUNING