Full-Stack Engineer - AI Systems

1. Role Overview

Mercor is seeking experienced full-stack engineers to work on an exciting opportunity to advance the frontier of AI.

2. Key Responsibilities

• Write product specifications precise enough that a competent engineer could build the application, and unambiguous enough to grade automatically
• Build a complete reference implementation of each specification that passes every criterion you have written
• Author browser-driven acceptance criteria that verify real user-visible behavior, not implementation details
• Calibrate task difficulty by running frontier models against your task and tuning until it lands in the target band
• Verify each task fails cleanly against an empty repository, so no criterion can be satisfied without genuinely building the feature

3. Ideal Qualifications

• 3+ years of professional full-stack engineering, having personally shipped and operated web applications
• Fluency in at least one modern frontend framework and one backend runtime, with working comfort across several
• Hands-on experience implementing auth, permissions, payment flows, and file upload in production, and knowing where each one usually breaks
• Ability to specify a system precisely in writing: the specification and its criteria are the product
• Comfort with Docker, git at commit level, and command-line tooling
• Prior experience building evaluations, benchmarks, or test suites for AI systems is a strong plus