Full Stack Software Engineer at Mercor

Full Stack Software Engineer | $50–65/hr | Remote (US) | AI Lab Placement

Join a leading AI lab's GenAI team and help build foundational AI models from the ground up. As a Full Stack Software Engineer, you'll work directly with the lab's engineering manager to build, integrate, and stress-test real software on top of frontier models before they ship. This is a full-time, 40-hour/week W-2 position with Cincinnatus LLC, placing you within an elite AI research environment.

Key Responsibilities

• Build and ship full-stack applications, services, and internal tools in Python, Java, Rust, C#, C++, or TypeScript that exercise frontier model capabilities end to end.
• Integrate pre-release model APIs into working software, including tool interfaces, evaluation harnesses, and telemetry scaffolding.
• Diagnose and document model and integration failure modes, translating engineering observations into clear written feedback for the research team.
• Prototype rapidly against shifting requirements, delivering working increments with minimal up-front specification.
• Collaborate with the engineering manager and peers to maintain code quality, architecture consistency, and technical documentation.

Core Qualifications

• 3+ years of professional experience building and shipping production software at a recognized, top-tier organization.
• Production proficiency in at least one of Python, Java, Rust, C#, or C++, plus working knowledge of a second language.
• Hands-on full-stack experience: backend services and APIs, a modern front-end framework (React or equivalent), relational or document databases, and cloud deployment.
• Demonstrated ability to onboard onto unfamiliar codebases and deliver working code quickly with minimal ramp-up.
• Strong written communication skills with the ability to explain complex technical decisions clearly.
• Availability for at least 40 hours/week during weekdays.

Cincinnatus LLC is an Equal Employment Opportunity employer. We welcome applicants of all backgrounds and do not discriminate on the basis of race, religion, gender, age, disability, or any other protected characteristic.