Software Engineer, Full Stack (Python, Java, Rust, C#, C++)

HumanitApp; Northern (KY); Hybrid; USD 69,000 - 90,000; Full time

Job summary

Cincinnatus LLC is seeking a talented Full-Stack Software Engineer to join a leading AI lab's GenAI team. You will build production-ready software across Python, Java, Rust, C#, C++, and TypeScript, integrating with frontier model APIs and deploying to the cloud.

You will collaborate with the AI lab's engineering manager, contribute code early, and commit to 40 hours per week in a W-2 arrangement. Candidates should have 3+ years of production software experience and a proven ability to onboard

Qualifications

• 3+ years of dedicated professional experience building and shipping production software at a recognized, top-tier organization.
• Proficiency in at least two languages among Python, Java, Rust, C#, C++, TypeScript.
• Hands-on experience with backend services, APIs, a modern frontend framework (React), databases, and cloud deployment.
• Ability to onboard onto an unfamiliar codebase and deliver working code quickly.
• Evidence of career progression.
• Commitment to 40 hours/week on weekdays.
• Strong written communication to explain complex decisions.

Responsibilities

• Build and ship full-stack applications, services, and internal tools across Python/Java/Rust/C#/C++/TypeScript.
• Integrate pre-release model APIs into working software with scaffolding and telemetry.
• Diagnose model and integration issues and provide clear feedback to research.
• Prototype quickly against changing requirements delivering working increments.
• Collaborate to maintain code quality, architecture, and documentation.

Skills

Python

Java

Rust

C#

C++

TypeScript

Education

Bachelor's degree in CS or related field

Tools

React

PostgreSQL

MongoDB

Job description

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 Full-Stack Software Engineers with hands-on production experience 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

• 3+ years of dedicated professional experience building and shipping production software at a recognized, top-tier organization.
• Production experience in at least one of Python, Java, Rust, C#, or C++, plus working proficiency in a second language; this cohort is intentionally staffed across multiple language ecosystems.
• Hands-on experience across the stack: backend services and APIs, a modern front-end framework (React or equivalent), relational or document databases, and cloud deployment.
• 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. Cincinnatus serves as the employer of record for these engagements, providing W-2 employment, payroll, benefits, and compliance, while placing employees directly within client teams to work on high-impact initiatives.

Equal Employment Opportunity: Cincinnatus is proud to be an Equal Employment Opportunity employer. We do not discriminate based upon race, religion, color, national origin, sex (including pregnancy, childbirth, reproductive health decisions, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, genetic information, political views or activity, or any other legally protected characteristic.

AI evaluation Clinical reasoning Python Research

Who this role may fit

This opportunity may suit professionals with relevant experience in AI evaluation, Clinical reasoning, Python, Research. Review the official description and requirements before applying.

Compensation context

The listing states $50 - $65 / hour. Confirm the final rate, workload, and payment terms during the official application process.

• You can show recent, specific work involving AI evaluation, Clinical reasoning, Python.
• The listed commitment of 40 hours/week fits your schedule.
• You can communicate your reasoning clearly in the application language.
• You are comfortable with project availability and hours varying over time.