Senior HTML/CSS Developer – AI Training

About the role

Prolific is seeking senior HTML/CSS developers to join its Expert Network and help train cutting‑edge AI models. You will evaluate AI‑generated frontend code, provide feedback, and ensure high‑quality, accessible implementations.

Key responsibilities

• Review AI‑generated HTML/CSS for functional correctness, semantic structure, and best‑practice compliance.
• Validate the logical explanations accompanying AI layout and styling solutions.
• Execute rendering tests across browsers to confirm visual fidelity and cross‑browser behavior.
• Annotate model performance, highlighting issues such as inaccessible markup, inefficient selectors, or deprecated properties.
• Provide structured feedback to improve the model’s reasoning around responsive design and component architecture.

Required profile

• BSc or higher in Computer Science, Software Engineering, Web Development, or a related field.
• Proven senior‑level experience as a Frontend Developer or UI Engineer specializing in HTML/CSS.
• Deep knowledge of the CSS cascade, specificity, box model, Flexbox, CSS Grid, and WCAG accessibility standards.
• Commitment to delivering clean, semantic markup and maintainable CSS following BEM methodology and modern standards.

Required skills

• HTML5
• CSS3/4 (custom properties, animations, modern layout systems)
• Tailwind CSS, SASS/SCSS, CSS Modules
• Flexbox and CSS Grid
• BEM methodology and design tokens
• Accessibility auditing tools (axe, Lighthouse)
• Browser DevTools and cross‑browser testing platforms

What we offer

• Paid tasks at rates up to $40 per hour, depending on experience.
• Flexible, task‑based work that can be completed in one‑hour uninterrupted blocks.