HTML/CSS - Senior Developers - AI Training - Portland, USA

prolificacademicltd; United States; Remote; USD 45,000 - 65,000; Full time

Job summary

Prolific Academic Ltd is seeking a senior frontend developer focused on HTML and CSS to contribute to paid tasks training AI systems. You will review generated markup, explain layout decisions, and ensure accessibility and cross-browser compatibility.

Remote role with flexible hours; responsibilities include building responsive components, validating CSS, and providing structured feedback on code quality. Up to $40 per hour based on skills and experience.

Qualifications

• Bachelor's degree or higher in CS, software engineering, web development, or related field.
• Experience as a senior frontend developer/UI engineer focused on HTML/CSS.
• Ability to build complex responsive layouts and components without frameworks.
• Strong knowledge of CSS cascade, specificity, box model, Flexbox, Grid, accessibility, and browser compatibility.
• Proficiency with HTML5 and modern CSS, plus browser dev tools and accessibility tests.

Responsibilities

• Assess generated markup and styles for correctness, semantic structure, and maintainability.
• Check explanations of layout and styling decisions for technical soundness.
• Render code and inspect appearance and behavior across browsers.
• Flag accessibility problems, inefficient selectors, deprecated markup, and invalid CSS.
• Give feedback on responsive layouts, component structure, and design system reasoning.

Skills

HTML & CSS

Responsive layouts

Accessibility standards

Cross-browser testing

Design systems familiarity

Education

Bachelor's degree in CS or related field

Tools

Browser DevTools

Tailwind CSS

Sass/SCSS

CSS Modules

BEM methodology

Job description

Role overview

Contribute senior frontend expertise to paid tasks that train and evaluate AI systems' ability to produce reliable HTML and CSS. Work involves reviewing generated code and explanations, checking rendered results, and giving structured feedback; tasks may require up to an hour of uninterrupted work.

Responsibilities

• Assess generated markup and styles for correctness, semantic structure, and maintainability.
• Check whether explanations of layout and styling decisions are technically sound.
• Render code and inspect its appearance and behavior across browsers.
• Flag accessibility problems, inefficient selectors, deprecated markup, and invalid CSS.
• Give feedback on responsive layouts, component structure, and design system reasoning.

Requirements

• A bachelor's degree or higher in computer science, software engineering, web development, or a related field.
• Professional experience as a senior frontend developer or UI engineer focused on HTML and CSS.
• Ability to build complex responsive layouts and components independently, including without frameworks.
• Strong knowledge of the CSS cascade, specificity, box model, Flexbox, Grid, accessibility standards, and browser compatibility.
• Skilled in producing semantic HTML and maintainable CSS, with familiarity with BEM, design tokens, and modern standards.
• Proficiency with HTML5 and modern CSS, plus browser developer tools and accessibility or cross-browser testing tools.

Nice to have

• Experience with Tailwind CSS, Sass/SCSS, CSS Modules, or component-based design systems.
• Familiarity with CSS custom properties, animations, and modern layout techniques.

Benefits and work setup

• Remote participation with flexible hours; tasks vary in length, and some require an uninterrupted hour.
• Paid tasks may offer up to $40 per hour depending on skills and experience.
• Applicants complete a 10-15 minute skills assessment before being invited to participate.