Senior Software Engineer, Full Stack (Python, Java, Rust, C#, C++)
Join a leading AI lab's cutting-edge GenAI team to be at the core of the AI revolution, where your expertise fuels the development of the most advanced Large Language Models.
- Pay
- Firm hourly pay: $90-$110 per hour
- Location
- United States
- Eligibility
- Remote; check the U.S. location wording
- Qualification difficulty
- Selective
How current is this information?
The public role and application path were checked. Details can still change; this is not an endorsement or guarantee.
- Platform
- Mercor
- Fit category
- Software engineering
- Listing/source checked
- Sep 26, 2026
- Inventory presence checked
- Sep 28, 2026
- Apply link checked
- Aug 22, 2026
Application
Continue to the current Mercor listing
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What this role involves
Join a leading AI lab's cutting-edge GenAI team to be at the core of the AI revolution, where your expertise fuels the development of the most advanced Large Language Models. 1. Overview Join a leading AI lab's cutting-edge GenAI team and help build foundational AI models from the ground up.
We're seeking talented Senior Full-Stack Software Engineers with deep, hands-on production expertise across modern application stacks — Python, Java, Rust, C#, C++, and TypeScript — to build, integrate, and stress-test real software on top of frontier models before they ship. Engineers work directly with the AI lab's engineering manager on fast-moving projects and are expected to onboard quickly and contribute working code early. This is a full-time commitment of 40 hours per week.
This is a W-2 employment position with Cincinnatus LLC, with the opportunity to be placed at a leading AI Lab as part of their extended workforce. 2.
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 the surrounding scaffolding: tool interfaces, evaluation harnesses, and telemetry. Diagnose and document model and integration failure modes surfaced while building, translating engineering observations into clear written feedback for the research team.
Prototype quickly against shifting requirements, delivering working increments with limited up-front specification. Collaborate with the engineering manager and other engineers to maintain consistency in code quality, architecture, and technical documentation. 3. Core Qualifications 6+ years of dedicated professional experience building and shipping production software at a recognized, top-tier organization, including ownership of systems end to end.
Deep production experience in at least one of Python, Java, Rust, C#, or C++, plus demonstrated delivery in a second language across a different ecosystem — this cohort is intentionally staffed across multiple language ecosystems. Hands-on ownership across the stack: backend service and API design, a modern front-end framework (React or equivalent), data modelling, and cloud deployment and operations. Demonstrated ability to onboard onto an unfamiliar codebase and deliver working code quickly with minimal ramp-up.
Demonstrable career progression. Ability to engage reliably for at least 40 hours/week during weekdays. Strong written communication skills and the ability to explain complex technical decisions clearly. About Cincinnatus LLC: Cincinnatus LLC is an enterprise staffing company that partners with leading technology companies to source and employ highly skilled professionals for contingent and contract-based opportunities.
Before you apply
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Why it may fit
- Professionals whose experience matches the current Senior Software Engineer, Full Stack (Python, Java, Rust, C#, C++) requirements.
- Applicants comfortable completing Mercor's role-specific assessment.
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Reasons to pause
- You cannot meet the listing's stated remote or location eligibility.
- You need guaranteed acceptance, hours, or project duration.
Still to verify
- Review the official Mercor listing before applying. Requirements, screening, pay, hours, and project availability can change.
- The reviewed listing had limited public detail; check the current platform page for the full requirements.
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- Complete Mercor's role-specific application or assessment.
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