Full-Stack Engineer - Ai Systems

Mercor; San Francisco (CA); Hybrid; GBP 51,000 - 82,000; Full time

Job summary

Mercor connects elite creative and technical talent with leading AI research labs. This remote, contract role targets a skilled Full-Stack Software Engineer to write precise specifications, build reference implementations, and verify acceptance criteria across frontend and backend systems.

You will work with authentication, permissions, payments, and file uploads in production, using Docker, Git, and CLI tooling to ensure robust, reproducible features.

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 development and automatic grading.
• Build complete reference implementations meeting 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

Frontend frameworks

Backend runtimes

Auth & permissions

Payment flows

File uploads

Docker

Git

CLI tools

Writing specs

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.