Product Web Developer Engineer Job at Stealth AI Startup in Sonoma

Help craft intelligent, opinionated interfaces that don’t just look magical—they are.

About Noumena

Noumena is an AI research lab and product company focused on usable intelligence. We’re building tightly integrated systems that reason, adapt, and evolve in context—starting with tools we use ourselves to accelerate research and product development. These tools generate high-signal feedback loops that power the training of the next generation of high-performance, specialized models.

We design, own, and operate the full stack—from infrastructure to interface. Every layer is designed to work together, compounding in capability, precision, and feedback over time. The result is not just smarter models—but systems that actually work in practice.

About the Role

We’re hiring a Product Web Developer Engineer to lead the design and implementation of our core user-facing product experiences—interfaces where real-time model capabilities meet complex, high-leverage workflows.

You won’t just be consuming APIs or polishing views. You’ll be building the system where model outputs become usable intelligence: structured, opinionated interfaces that evolve with both user needs and model behavior.

We’re currently focused on coding and planning tools for high-agency users—engineers, researchers, and designers pushing the edge of what AI can actually do. You’ll help define the experience layer that makes that possible.

What You’ll Own

• Architect and implement real-time, high-complexity product interfaces
• Work closely with infra and model teams to shape how capabilities are surfaced in the UI
• Design interaction patterns that reflect system constraints, not obscure them
• Translate ambiguous user needs and design ideas into fast, expressive, production-grade UX
• Prototype, test, and iterate quickly—across workflows, models, and tooling
• Help define how Noumena’s tools evolve with usage, training, and model development

You May Be a Good Fit If You:

• Have deep experience with React, Next.js, TypeScript, and dynamic UI systems
• Thrive in zero-to-one product environments where the interaction layer is the innovation
• Have built developer tools, productivity systems, or exploratory UIs
• Think in systems—not just views or states—and care about long-term maintainability
• Can hold product, design, and implementation in your head at once—and move fast across them
• Care deeply about speed, clarity, and interaction flow—not just styling polish

Strong Candidates May Also Have Experience With:

• Working across the stack in TypeScript, Python, or Rust
• Building editors, interactive tools, or structured/sandboxed interfaces
• Real-time systems (token streaming, multi-threaded workflows, etc.)
• Designing for data-heavy, technical, or domain-specific user groups
• Modeling feedback loops between usage and system behavior

Why This Role Matters

You’ll help define how usable intelligence actually feels: where model outputs become structured, navigable, and deeply intuitive product experiences. This is where AI stops being a demo—and becomes a system.

Team & Culture

We’re a small, senior team that values autonomy, sharp thinking, and low-ego collaboration. We’re remote-flexible but value time together, especially for product shaping and launches. We care deeply about craft and performance—and we hire people who want to build enduring systems that feel great to use.