Frontend Code Evaluation Specialist Desarrollador Fullstack

About the job

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.

Resources & Support

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