Founding Software Engineer - AI Evaluation & Data Infrastructure

Location: San Francisco

compensation: $150K - $240K

We are building the most complex infrastructure that powers frontier data creation for agentic and hard reasoning workflows, helping push the frontier of LLMs and AI Agents. We work with all 5 of the leading AI labs and are experiencing sharp hockey stick growth. We are seeking a Founding Software Engineer with end-to-end ownership to build the systems that power data and evaluation for the next generation of AI.

This is a dynamic, high-impact role that offers immense breadth of ownership over projects that push the frontier of AI evaluation. You will move fluidly across the entire stack, from research prototyping to distributed cloud infrastructure and user-facing analytics. You must be comfortable with constant context switching and relentless shipping in a talent-dense environment.

What You’ll Do:

• System Design & Build: Design and build scalable, production systems, including RL environments, APIs, and human-in-the-loop platforms.
• Full-Stack Ownership: Contribute across the entire stack, which includes Next.js dashboards, Kafka data pipelines, and complex infrastructure (Kubernetes, Redis, Elasticsearch).
• Research to Production: Prototype new AI/RL environments from research papers and quickly transition them into reliable, distributed experiments.
• Collaboration: Work closely and collaboratively across research, product, and design teams to ship high-leverage features quickly.
• Code & Reliability: Write clean, maintainable code, uphold high standards in code reviews and design discussions, and solve real-world scalability and reliability challenges.
• Core Infrastructure: Directly contribute to the core infrastructure powering data and evaluation for leading AI labs and high-growth companies.

Requirements

• Experience: 0 – 3 years of experience as a full-stack software engineer.
• Technical Stack: Strong proficiency and willingness to work across our core stack: TypeScript/JavaScript, Next.js, React, Node.js, Python, Kubernetes, and Kafka.
• Full-Stack Mentality: Ability to shift context between front-end UI, backend services, and distributed data infrastructure.
• Mindset: Exceptional drive and intensity, a focus on taking ownership, and comfort working at breakneck speed in a high-growth environment.
• Location: Ability to work 5 days a week in our FiDi (SF) office (on-site).

Preferred Qualifications:

• Experience in rigorous environments in tech or finance (e.g., quantitative trading, top-tier engineering firms).
• Familiarity with cloud platforms (AWS, GCP).

Benefits

• Compensation: Highly competitive salary range of $150,000 – $240,000 (Flexible for a very strong background).
• Equity: Generous Founding Equity (0.5% to 1.0%) for true alignment with company success.
• Impact: Work with the leading AI labs and immediately contribute to the frontier of LLM and AI Agent capabilities.
• Culture: Join an extremely talent-dense, tight-knit team whose co-founders bring expertise from firms like Citadel, Google, and Meta.
• Relocation & Visa: Visa sponsorship is available for exceptional candidates.

Due to the high volume of applications we anticipate, we regret that we are unable to provide individual feedback to all candidates. If you do not hear back from us within 4 weeks of your application, please assume that you have not been successful on this occasion. We genuinely appreciate your interest and wish you the best in your job search.

Commitment to Equality and Accessibility:

At MLabs, we are committed to offer equal opportunities to all candidates. We ensure no discrimination, accessible job adverts, and providing information in accessible formats. Our goal is to foster a diverse, inclusive workplace with equal opportunities for all. If you need any reasonable adjustments during any part of the hiring process or you would like to see the job-advert in an accessible format please let us know at the earliest opportunity by emailing human-resources@mlabs.city.

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