Full-Stack Engineer - AI Systems

mercor; Deutschland; Remote; EUR 61,000 - 98,000; Full time

Job summary

Mercor is seeking a freelance full-stack software engineer for a remote contract role. You will write precise specifications, build reference implementations, and author browser-driven acceptance criteria to verify behavior.

You will calibrate task difficulty using frontier models to reach target performance and ensure robust development by testing fail scenarios against empty repositories. The ideal candidate has 3+ years of experience, proficiency in a frontend framework and a backend runtime,

Qualifications

• 3+ years of professional full-stack engineering experience.
• Fluency in at least one modern frontend framework and one backend runtime.
• Experience with auth, permissions, payment flows, and file uploads in production.
• Ability to specify systems precisely in writing.
• Comfort with Docker, Git, and command-line tooling.

Responsibilities

• Write precise product specifications for application development and automatic grading.
• Build complete reference implementations that meet all written criteria.
• Author browser-driven acceptance criteria to verify user-visible behavior.
• Calibrate task difficulty using frontier models to achieve target performance.
• Verify tasks fail cleanly against empty repositories to ensure genuine feature development.

Skills

Full-stack development

Frontend framework

Backend runtime

Auth & payments

CLI tooling

3+ years experience

Tools

Docker

Git

Command-line

Job description

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: Full-Stack Software Engineer Type: Contract Compensation: $50–$80/hour Location: Remote

Role Responsibilities

• Write precise product specifications for application development and automatic grading.
• Build complete reference implementations that meet all written criteria.
• Author browser-driven acceptance criteria to verify user-visible behavior.
• Calibrate task difficulty using frontier models to achieve target performance.
• Verify tasks fail cleanly against empty repositories to ensure genuine feature development.

Qualifications Must-Have

• 3+ years of professional full-stack engineering experience.
• Fluency in at least one modern frontend framework and one backend runtime.
• Experience with auth , permissions , payment flows , and file upload in production.
• Ability to specify systems precisely in writing.
• Comfort with Docker , Git , and command-line tooling.

Preferred

• Experience building evaluations, benchmarks, or test suites for AI systems .