Frontend Developer — HTML & CSS for AI Systems

About OpenTrain

OpenTrain is the #1 platform for people building careers in AI training and data labeling. We help contributors discover projects, build a unified portfolio, and grow lasting freelance careers doing the human work that teaches AI.

This role is posted through OpenTrain because front-end developers like you shape the real interfaces that generate, collect, and evaluate the examples modern models learn from.

About AI training work

AI training (data labeling, annotation, and human feedback) is the human side of modern AI development: people create, review, and rate examples that models learn from. Contributors often work remotely, choose flexible hours, and help shape how state-of-the-art systems behave.

This front-end role directly supports AI training by building UIs used to collect and evaluate programming and rating tasks (e.g., coding evaluations and response ratings).

The role

We are recruiting a Frontend Developer to design, implement, and maintain the user interfaces that power AI systems and labeling workflows. You will create responsive, accessible, and reusable UI components that deliver real-world input to models and support evaluators and annotators.

This is a remote, part-time contractor position (20+ hours/week). Work is worldwide and conducted in English.

• Employment type: Contractor, Part-time
• Time requirement: 20+ hours/week
• Language: English
• Location: Remote, worldwide

What you'll do

Your day-to-day work will focus on turning design files into interactive interfaces, integrating front ends with APIs, and ensuring components are performant and testable. You will collaborate with UX designers and backend engineers to deliver integrated solutions for AI data collection and evaluation.

• Translate design files into clean, responsive, reusable UI components.
• Implement front-end logic with Angular, Vue.js, React, Bootstrap and jQuery where applicable.
• Integrate UIs with backend services and APIs (CakePHP/MySQL integrations required).
• Write and run unit and automated tests; troubleshoot and resolve front-end issues.
• Optimize performance and ensure accessibility across devices and screen sizes.

Requirements

You must have hands-on experience and demonstrable skills in the technologies and practices listed below. This role is open to entry-level candidates who meet the technical requirements.

• Expert-level proficiency in HTML, CSS, and JavaScript.
• Hands-on experience with Angular, Vue.js, React, and Bootstrap.
• Solid experience converting design files into interactive interfaces.
• Proficient integrating back-end services/APIs, especially CakePHP and MySQL.
• Strong background in developing scalable UI components and modular codebases.
• Experience with unit and automation testing methodologies.
• Excellent problem-solving, communication, and collaboration skills.

Helpful background (nice to have)

The following are not required but will make you more effective in the role and may influence compensation or scope of work.

• Experience deploying web apps on cloud platforms.
• Familiarity with advanced debugging tools and front-end performance optimization.
• Prior work on large-scale, customer-focused software projects.

Compensation, data work, and schedule

Pay is hourly, listed between $30 and $80 USD per hour. This is a contract role with flexible scheduling; expect to commit at least 20 hours per week.

The work supports AI training data types focused on computer code and programming evaluation, including coding/coding-evaluation and rating tasks.

• Pay type: Hourly (USD) — range $30–$80/hr.
• Data type: Computer code / programming; label types include coding evaluation and rating.
• (project-specific tools).

How to apply

If you meet the technical requirements, create or sign in to your OpenTrain account and apply to this posting. Include examples of front-end work or a portfolio that demonstrates responsive components and integrations with APIs/backends.

Applications should highlight relevant projects using Angular/Vue/React, any CakePHP/MySQL integrations, and tests or CI practices you’ve implemented.

• Prepare a short portfolio or links to code samples and a resume.
• Describe your availability in hours per week and earliest start date.