HTML/CSS - Senior Developers - AI Training - Washington DC, USA

Prolific; Washington (District of Columbia); On-site; USD 45,460 - 64,747; Part time

Benefits offered by this job

Flexible hours

Ability to work from home

Job summary

Prolific is seeking Senior HTML/CSS Developers to join its Expert Network in Washington, DC. You will help train AI models by evaluating HTML/CSS accuracy, validating logic, and conducting execution testing. Ideal candidates have a BSc in Computer Science or a related field, extensive frontend development experience, and mastery of modern HTML/CSS standards. The position offers competitive pay rates up to $40/hr, flexible hours, and the ability to work remotely.

Qualifications

• Real-world experience as a Senior Frontend Developer or UI Engineer specializing in HTML/CSS.
• Ability to independently build complex layouts without frameworks.
• Expert understanding of accessibility standards (WCAG) required.

Responsibilities

• Review AI-generated HTML/CSS for correctness and best practices.
• Verify model-generated markup in different environments.
• Provide structured feedback on responsive design and component architecture.

Skills

Building complex responsive layouts

Expert understanding of CSS cascade and box model

Clean semantic markup

Cross-browser compatibility

High proficiency in HTML/CSS

Education

BSc or higher in Computer Science, Software Engineering or related field

Tools

Tailwind CSS

SASS/SCSS

Browser DevTools

Job description

HTML/CSS - Senior Developers - AI Training - USA

About Prolific

Prolific is not just another player in the AI space – we are building the biggest pool of quality human data in the world.

The role

We're looking for Senior HTML/CSS Developers to join our Expert Network to help train and evaluate cutting‑edge AI models. If you have a background in Software Engineering or Frontend Development, we'll send you a quick 10‑ to 15‑minute test to assess your skills. If successful, you'll be invited to join Prolific as a participant, where you'll get paid to help AI understand and produce high‑quality frontend code and design implementation.

Researchers pay up to $40/hr, depending on skills and experience. You must be prepared to complete paid tasks that require one hour of uninterrupted work, though many are shorter.

What you’ll bring

• Educational Background: a BSc or higher in Computer Science, Software Engineering, Web Development, or a closely related technical field.
• Professional Experience: real‑world experience as a Senior Frontend Developer or UI Engineer specialising in HTML/CSS.
• Coding Proficiency: ability to independently build complex, responsive layouts and components without relying on frameworks or libraries.
• Deep Domain Knowledge: expert understanding of the CSS cascade, specificity, the box model, Flexbox, CSS Grid, accessibility standards (WCAG), and cross‑browser compatibility.
• Code Quality: a high standard for clean, semantic markup and maintainable CSS, including adherence to BEM methodology, design tokens, and modern CSS standards.

What you’ll be doing in the role

• Evaluate Code Accuracy: review AI‑generated HTML/CSS for functional correctness, semantic structure, and adherence to best practices.
• Validate Logic & Reasoning: audit the step‑by‑step explanations provided by AI for layout solutions and styling approaches to ensure they are technically sound.
• Conduct Execution Testing: render model‑generated markup and stylesheets in appropriate environments to verify visual output and cross‑browser behaviour.
• Annotate Model Performance: identify areas where a model produces inaccessible markup, inefficient selectors, deprecated attributes, or hallucinated CSS properties.
• Refine Technical Logic: provide structured feedback on how models reason through responsive design, component architecture, or design system implementation.

Key Technologies

• Core Languages: expert mastery of HTML5 and CSS3/4, including custom properties, animations, and modern layout systems.
• Frameworks & Methodologies: extensive experience with Tailwind CSS, SASS/SCSS, or CSS Modules, and familiarity with component‑driven design systems.
• Testing & Tools: proficiency with browser DevTools, accessibility auditing tools (axe, Lighthouse), and cross‑browser testing platforms.

Benefits

You can start in just 15 minutes, earning competitive pay rates up to $40/hr, with flexible hours and the ability to work from home.

By submitting your application, you agree that Prolific may collect your personal data for recruiting and global organisation planning. Prolific's Candidate Privacy Notice explains what personal information Prolific may process, where Prolific may process your personal information, its purposes for processing your personal information, and the rights you can exercise over Prolific use of your personal personal information.