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

Weekday AI

1d • $90 - $110

About The Position

This role is for one of our clients. Join a leading AI research organization at the forefront of generative AI and contribute to the development and evaluation of advanced Large Language Models. We are seeking experienced Senior Full-Stack Software Engineers with strong production expertise across modern software ecosystems, including Python, Java, Rust, C#, C++, and TypeScript. In this role, you will build, integrate, and stress-test production-quality software that interacts with frontier AI models. You will work closely with engineering and research teams on fast-moving initiatives, rapidly adapt to new codebases and requirements, and contribute working code early in the engagement. This is a full-time role requiring 40 hours per week.

Requirements

• 6+ years of professional software engineering experience building and shipping production systems at established technology organizations or comparable environments.
• Strong hands-on production expertise in at least one of Python, Java, Rust, C#, or C++, along with meaningful professional experience delivering software in a second programming language or ecosystem.
• Demonstrated full-stack engineering experience covering: Backend services and API development, Modern frontend frameworks such as React or equivalent, Database and data-model design, Cloud infrastructure and deployment, Production operations and system reliability.
• Experience owning software systems end to end, from design and implementation through deployment, monitoring, debugging, and ongoing improvement.
• Ability to quickly understand unfamiliar architectures, repositories, development environments, and technical requirements, then begin delivering production-quality code with minimal ramp-up.
• Demonstrated career progression and increasing technical ownership throughout your engineering career.
• Strong understanding of software engineering best practices, including testing, version control, code review, debugging, system design, and technical documentation.
• Strong written and verbal communication skills, with the ability to clearly explain technical decisions, trade-offs, implementation details, and system behavior.
• Ability to commit reliably to 40 hours per week during weekdays.

Nice To Haves

• Experience working with AI/ML systems, LLM APIs, AI coding tools, or model evaluation workflows is advantageous.

Responsibilities

• Build full-stack applications: Design, develop, and ship production-quality applications, backend services, APIs, and internal tools using technologies such as Python, Java, Rust, C#, C++, and TypeScript.
• Integrate AI models: Integrate pre-release and frontier model APIs into functional software systems, including tool interfaces, evaluation frameworks, telemetry, and supporting infrastructure.
• Develop across the stack: Work across backend services, APIs, databases, frontend applications, cloud infrastructure, and deployment environments to deliver complete solutions.
• Test and stress-test systems: Build applications and testing frameworks that exercise model capabilities and identify performance, reliability, integration, and usability issues.
• Identify failure modes: Diagnose technical and model-related failures encountered during development and document findings clearly for engineering and research teams.
• Prototype rapidly: Translate evolving requirements into working software, delivering high-quality iterations with limited upfront specifications.
• Collaborate with engineering teams: Partner with engineering managers and fellow developers to maintain strong standards for architecture, code quality, testing, documentation, and maintainability.

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Education Level: No Education Listed