Javascript - Senior Developers - AI Training - Jacksonville, USA

Prolific; Jacksonville (FL); On-site; USD 80,000 - 110,000; Full time

Benefits offered by this job

Competitive pay rates

Flexible hours

Work from home

Job summary

Prolific is seeking a Senior HTML/CSS Developer to join our Expert Network and help train AI models. The role involves evaluating AI-generated HTML/CSS for accuracy, conducting execution testing, and providing structured feedback on model performance. Ideal candidates will have a BSc in a related field and real-world experience in frontend development. Enjoy competitive pay rates and the flexibility to work from home in Jacksonville, Florida.

Qualifications

• Expert understanding of the CSS cascade, specificity, box model, Flexbox.
• Real-world experience as a Senior Frontend Developer or UI Engineer.
• Ability to spot rendering issues and non-standard markup.

Responsibilities

• Review AI-generated HTML/CSS for correctness and structure.
• Audit AI's explanations for technical soundness.
• Render model-generated markup for visual verification.

Skills

HTML/CSS mastery

Responsive design

Attention to detail

Education

BSc or higher in Computer Science or related field

Tools

Browser DevTools

Accessibility auditing tools

Cross-browser testing platforms

Job description

Overview

HTML/CSS - Senior Developers - AI Training

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.

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.
• Attention to Detail: ability to spot subtle rendering issues, accessibility violations, specificity conflicts, or deprecated/non-standard usage in model-generated code

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 (e.g., axe, Lighthouse), and cross-browser testing platforms.
• Integration & API: strong understanding of how HTML/CSS interacts with JavaScript frameworks, CMS platforms, and design handoff tools such as Figma.

Why Prolific is a great platform to join as a Participant

Joining our Expert Network will give you the chance to influence the AI models of the future using professional expertise. Once you pass our assessment, you can join Prolific in just 15 minutes, and start enjoying competitive pay rates, flexible hours, and the ability to work from home.

We\'ve built a unique platform that connects researchers and companies with a global pool of participants, enabling the collection of high-quality, ethically sourced human behavioural data and feedback. This data is the cornerstone of developing more accurate, nuanced, and aligned AI systems.

We believe that the next leap in AI capabilities won\'t come solely from scaling existing models, but from integrating diverse human perspectives and behaviours into AI development. By providing this crucial human data infrastructure, Prolific is positioning itself at the forefront of the next wave of AI innovation – one that reflects the breadth and the best of humanity.

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