About Us NeoSigma is a product-driven research lab building the intelligence layer that helps close the feedback loop between your customers, products, and AI systems. We are a small, intensely technical team of researchers and engineers who have trained frontier-scale models and widely used AI products and agents at Parallel Web, Essential AI, MIT, Apple, and Amazon. We are backed by world-class investors and leaders from Google DeepMind, OpenAI, Decagon and others. The Role We are looking for a AI Engineer to build intelligent systems that learn from real-world usage. You will work across LLMs, agent architectures, evaluation pipelines, and production AI systems, turning cutting-edge research into reliable products. Some weeks you'll be developing novel AI capabilities and experimenting with new models. Other weeks you'll be shipping production features that help customers build smarter, more reliable AI applications. What you'll do: • Build SOTA agentic pipelines that mine production traces for failures mining, triaging, evaluations, and optimizations • Design and implement large-scale data processing systems that turn production agent traces into signal for evaluation and optimization • Design and run optimization loops that convert evaluation signal into measurable gains in agent behavior • Own the cost and latency profile of our ML systems as trace volume and customer count scale • Push novel evaluation and post-training research into production within weeks What we look for: • Hands-on experience shipping LLM-powered or agentic systems to real production environments • Strong instincts around evaluation design, post-training methods, and agent triaging • Comfortable working directly with customers and translating their constraints into system decisions • High bar for code quality, modularity, and systems that stay clean as they grow • Ability to move fast in ambiguous territory and turn open problems into clear, executable plans • Bachelor’s degree in Computer Science, Engineering, or a related field (or equivalent practical experience) Our Core Values: • Customer Obsession - We start with the customer and work backwards. We aim to earn trust through consistent delivery, thoughtful listening, and by obsessing over customers. • Intellectual Honesty - We operate with high trust and low ego. Ideas matter more than titles, and we communicate openly and directly while assuming good intent, even in strong disagreement. • Bias for Action - We set high standards and move quickly to meet them. We prefer building and learning with customers over debating in the abstract, and we iterate based on real feedback. • Extreme Ownership - We take responsibility for outcomes, not just tasks. Ownership means seeing problems through to completion and ensuring solutions truly work in practice. Benefits and perks • Competitive salary plus meaningful equity package • Comprehensive medical benefits and generous PTO • Flexible work arrangements • Direct impact on company direction and technical decisions • High ownership and the opportunity to make a career-defining impact • Visa sponsorship As a founding member, you’ll help define the technical foundation of NeoSigma. Your scope will grow with the company, from owning core systems end-to-end to shaping architecture, hiring, and engineering culture. This role has a natural path toward technical leadership or engineering management as the team scales.