Frontend Software Engineer

Hace 1 semana

valencia, província de valència, España Confidential Jornada completa

Frontend Engineer


Position: Frontend Engineer


Type: Freelance Hourly Contract


Compensation: $90/hour


Location: Remote


About the Opportunity

This opportunity is for experienced Frontend Engineers and Full-Stack Developers interested in evaluating AI-generated web interfaces and code.

The work focuses on comparing AI-generated frontend implementations against real-world reference websites, assessing both visual fidelity and underlying code quality .

This is an evaluation-focused role rather than a traditional development position. The key requirement is the ability to identify how a webpage is constructed, recognize technical shortcuts, and provide precise, evidence-based evaluations.

What You'll Do

  • Render a reference webpage and two AI-generated implementations at a 1920×1080 viewport and evaluate which version most accurately reproduces the reference.
  • Compare visual fidelity across different interface states, including layout, spacing, typography, colors, borders, images, layering, and overflow behavior .
  • Review the source code of AI-generated implementations and assess HTML structure, CSS architecture, responsiveness, maintainability, and implementation quality .
  • Identify technical shortcuts such as excessive hardcoded positioning, unnecessary absolute positioning, poorly structured markup, or image-based recreations.
  • Test responsive behavior across different viewport sizes and identify layout or usability defects.
  • Use browser DevTools to inspect elements, computed styles, DOM structure, and interactive states.
  • Provide specific, evidence-based written justifications explaining why one implementation is stronger than another.
  • Identify genuinely broken evaluation tasks while distinguishing them from tasks that are simply challenging.

Required Qualifications

  • 3–8 years of professional web development experience , primarily in frontend or full-stack engineering.
  • Strong hands-on experience with HTML, CSS, JavaScript, responsive web development, and modern frontend engineering practices .
  • Deep understanding of semantic HTML, Flexbox, CSS Grid, media queries, and responsive layouts .
  • Ability to read and understand both modern and legacy web layouts , including float-based and table-based designs.
  • Strong proficiency with browser Developer Tools , including DOM inspection, computed styles, viewport testing, and interactive state debugging.
  • Comfortable working from the command line, including extracting archives, running local development servers, and troubleshooting asset paths .
  • Sufficient JavaScript knowledge to understand how scripts interact with the DOM and user interactions.
  • Strong professional written English and the ability to provide clear, detailed technical justifications .
  • Strong attention to detail and the ability to identify subtle visual and structural differences.

Preferred Qualifications

  • Prior experience with RLHF, preference labeling, AI model evaluation, structured code review, or human-feedback projects .
  • Pixel-perfect design-to-code experience, including work with design systems, templates, or production web interfaces .
  • Knowledge of web accessibility , including ARIA, semantic landmarks, and heading hierarchy.
  • Familiarity with common failure patterns in AI-generated fr