Senior HTML/CSS Developer for AI Training (Remote UK)

Prolific; United States; Remote; USD 33,000 - 55,000; Part time

Job summary

Prolific is seeking Senior HTML/CSS Developers to join our Expert Network for training and evaluating cutting-edge AI models. You’ll review AI-generated HTML/CSS, assess semantic structure, and ensure accessibility and cross-browser compatibility, working on tasks that support researchers and industry partners.

The role emphasizes high-quality, semantic markup, a strong CSS skillset, and the ability to craft and critique robust frontend solutions.

Qualifications

• Educational background: a BSc or higher in Computer Science, Software Engineering, Web Development, or a closely related field.
• Professional experience: real-world experience as a Senior Frontend Developer or UI Engineer specialising in HTML/CSS.
• Coding proficiency: independently build complex, responsive layouts and components without relying on frameworks or libraries.
• Deep domain knowledge: CSS cascade, specificity, box model, Flexbox, CSS Grid, accessibility standards (WCAG), cross-browser compatibility.
• Code quality: semantic markup, maintainable CSS, BEM, design tokens, and modern CSS standards.

Responsibilities

• Evaluate AI-generated HTML/CSS for functional correctness, semantic structure, and best practices.
• Validate logic and reasoning in AI-provided explanations for layouts and styling.
• Conduct execution testing by rendering markup and stylesheets across environments.
• Annotate model performance by identifying inaccessible markup, inefficient selectors, deprecated attributes, or hallucinated CSS properties.
• Refine technical logic by giving feedback on responsive design, component architecture, or design system implementations.

Skills

HTML5

CSS3

Frontend Development

Education

BSc or higher in CS/SE/Web Dev

Tools

Tailwind CSS

SASS/SCSS

CSS Modules

Job description

Prolific is seeking Senior HTML/CSS Developers to join our Expert Network for training and evaluating cutting-edge AI models. You’ll review AI-generated HTML/CSS, assess semantic structure, and ensure accessibility and cross-browser compatibility, working on tasks that support researchers and industry partners.

The role emphasizes high-quality, semantic markup, a strong CSS skillset, and the ability to craft and critique robust frontend solutions.