Frontend Software Engineer (Remote | $70–$100/hr)

Synthires; España; Remote; EUR 45,000 - 65,000; Full time

Job summary

Synthires is seeking a frontend engineer to assess AI-generated frontend code, UI implementations, and web applications. You will work on improving accuracy, UI quality, and overall frontend performance in a fully remote setup.

Required are strong skills in HTML/CSS, React/Angular/Vue, and pixel-accurate UI delivery. You will build and review responsive interfaces, debug issues, and provide actionable feedback to AI coding tools.

Qualifications

• Degree or equivalent in a technical field.
• Experience in frontend development and UI engineering.
• Knowledge of modern frontend frameworks (React/Angular/Vue).
• Strong HTML/CSS, responsive design, and component-based architecture.
• Experience delivering pixel-accurate user interfaces and style guides.
• Proficient debugging, code review, and performance optimization.
• Ability to work independently in a fully remote environment.

Responsibilities

• Evaluate AI-generated frontend code, UI implementations, and web apps for quality and performance.
• Build and review responsive, accessible web interfaces.
• Identify bugs, edge cases, rendering issues, and accessibility concerns.
• Implement components, design systems, and interactive UI features.
• Ensure pixel-accurate UI across devices and screen sizes.
• Debug and refactor frontend codebases to improve performance and maintainability.
• Provide structured feedback to improve AI coding accuracy.

Skills

Frontend engineering

React/Angular/Vue.js

HTML/CSS

Pixel-accurate UI

Debugging

Independent work

Education

Bachelor's degree or equivalent in CS/SE/IT

Tools

Next.js

State management libraries

Frontend testing frameworks

API integration

Design systems

Git/GitHub/CI/CD

Job description

In this role, you'll apply your engineering expertise to evaluate AI-generated frontend code, user interfaces, web applications, and technical implementations. Your work will help improve the coding accuracy, reasoning, UI quality, and software engineering capabilities of next-generation AI systems.

No prior AI experience is required. Your frontend engineering expertise, programming skills, and experience building high-quality web interfaces are the primary qualifications for success in this role.

Responsibilities

• Evaluate AI-generated frontend code, web applications, and UI implementations for correctness, quality, maintainability, and performance.
• Build, review, and improve responsive, accessible, and user-friendly web interfaces.
• Review AI-generated implementations for bugs, edge cases, rendering issues, accessibility concerns, and performance bottlenecks.
• Implement and evaluate components, design systems, user interfaces, and interactive web features.
• Ensure pixel-accurate UI implementation while maintaining responsiveness across different devices and screen sizes.
• Debug and refactor existing frontend codebases to improve performance, scalability, and maintainability.
• Provide structured technical feedback to improve AI coding accuracy, reasoning, and frontend development capabilities.

Required Qualifications

• Bachelor's degree or equivalent professional experience in Computer Science, Software Engineering, Information Technology, or a related technical field.
• Professional experience in frontend engineering, frontend development, web development, or UI engineering.
• Experience with modern frontend frameworks such as React, Angular, Vue.js, or similar technologies.
• Strong understanding of HTML, CSS, responsive design, and component-based architecture.
• Experience implementing pixel-accurate user interfaces and component style guides.
• Strong skills in debugging, code review, performance optimization, and frontend problem-solving.
• Excellent analytical thinking, written communication, and attention to detail.
• Ability to work independently in a fully remote environment.

Preferred Qualifications

• Experience building large-scale web applications or production frontend systems.
• Familiarity with Next.js, state management libraries, frontend testing frameworks, and API integration.
• Experience with design systems, UI component libraries, and accessibility standards.
• Familiarity with Git, GitHub, CI/CD pipelines, and modern frontend development workflows.
• Familiarity with AI coding tools, AI-assisted development, or AI model evaluation.