Frontend Developer Nextjs

Amaris Group Sa; Barcelona; Remote; EUR 94,000 - 127,000; Full time

Job summary

Mercor seeks a Web Development Expert to join its remote team. The role emphasizes frontend mastery with HTML, CSS, and JavaScript, accessibility, and pixel-perfect layouts, requiring 3–8 years of professional web development experience.

You will render reference pages, judge reproductions, test responsiveness, and provide evidence-based justifications for design decisions, collaborating on model-evaluation projects with strong written English.

Qualifications

• 3–8 years of professional web development experience in frontend or full-stack work.
• Fluency across web eras and legacy layouts.
• Proficiency with hand-written HTML and CSS: semantic markup, flexbox, grid, media queries, and legacy layouts.
• Browser DevTools as muscle memory.
• Command-line comfort: static servers, broken image references.

Responsibilities

• Render a reference page and two candidate replications at 1920×1080; judge which is closer to the source.
• Diff visual fidelity including box model, typography, color, borders, and assets.
• Read source code of attempts and grade construction quality; compare correctness across viewports.
• Test responsiveness and identify defects like nav collapse at smaller widths.
• Provide evidence-based justifications for each preference with concrete reasoning.

Skills

Web development (3–8 years)

HTML

CSS

JavaScript

Accessibility

Responsive design

DevTools

Command-line tooling

English writing

Job description

Web Development Expert - Fully Remote | Upto $90/hr

Mercor connects elite creative and technical talent with leading AI research labs. Headquartered in San Francisco, our investors include Benchmark , General Catalyst , Peter Thiel , Adam D'Angelo , Larry Summers , and Jack Dorsey .

Position: Frontend Engineer
Type: Contract
Compensation: $90/hour
Location: Remote

Role Responsibilities

• Render a reference page and two candidate replications at 1920×1080. Judge which is the closer reproduction, state by state.
• Diff visual fidelity in detail: box model and spacing, typography (family, size, weight, line-height, letter-spacing), color and border treatment, image and asset handling, z-order, and overflow.
• Read the source of both attempts and grade construction quality. Distinguish a replication that is genuinely correct from one that merely looks correct at one viewport.
• Test responsiveness. Identify defects such as a nav bar that looks right at 1920px but collapses at 1400px.
• Write specific, evidence-cited justifications for every preference. Provide detailed explanations like "B nests the article body in a single absolutely-positioned div, so the text overlaps the footer below 1600px, while A uses normal document flow."
• Use the "this task is broken" escape hatch with judgment. Distinguish a task that genuinely cannot be completed from one that is merely hard.

Qualifications

Must-Have

• 3–8 years of professional web development experience in frontend or full-stack work.
• Fluency across web eras, including legacy layouts like used for layout.
• Command of hand-written HTML and CSS : semantic markup, flexbox, grid, media queries, and legacy float- and table-based layouts.
• Browser DevTools as muscle memory.
• Command-line comfort: unzipping an archive, standing up a static local server, and untangling a broken image reference.
• Enough JavaScript to read a page's scripts and understand their DOM impact.
• Professional written English for task justification.

Preferred

• Prior RLHF , preference-labeling, model-evaluation, or structured code-review work.
• Pixel-perfect design-to-code experience.
• Accessibility expertise (ARIA , semantic landmarks, heading hierarchy).
• Familiarity with how LLMs fail at code generation.
• Web scraping, archiving, or DOM-parsing background.
• More than one completed Mercor project and availability in contiguous multi-hour blocks.