Senior Open Source Design Engineer

About Arize AI is rapidly transforming the world. As generative AI reshapes industries, teams need powerful ways to monitor, troubleshoot, and optimize their AI systems. That’s where we come in. Arize AI is the leading AI & Agent Engineering observability and evaluation platform , empowering AI engineers to ship high-performing, reliable agents and applications. From first prototype to production scale, Arize AX unifies build, test, and run in a single workspace—so teams can ship faster with confidence. We’re a Series C company backed by top-tier investors, with over $135M in funding and a rapidly growing customer base of 150+ leading enterprises and Fortune 500 companies. Customers like Booking.com , Uber, Siemens, and PepsiCo leverage Arize to deliver AI that works. The Role We're looking for a Design Engineer to build ambitious interfaces at the frontier of AI development, evaluation, and observability. You'll design, prototype, and ship experiences that help AI teams understand, troubleshoot, and improve the systems powering their next-generation applications. Here's what makes this role different: Modern AI work is no longer purely human-driven. Arize Phoenix is a platform used by AI teams and AI agents such as Claude Code. You won't just craft great UX. You'll pioneer great AX (Agent Experience)—product surfaces that are delightful for people and interoperable, safe, and legible for agents. What You’ll Work On Product & Interface Design • Design and build compelling product experiences for Arize Phoenix across UI-driven and programmatic workflows • Create interactive visualizations for embeddings, traces, evaluation runs, and agent/tool workflows • Develop reusable components and templates for our design system, from concept to production Agent Experience (AX) • Build Agent Experience primitives: interaction contracts, human-in-the-loop workflows, and agent-friendly UI surfaces • Enable agents to query, navigate, trigger evaluations • Shape the patterns that define how humans and AI agents collaborate within a shared workspace Prototyping & Exploration • Prototype new AI features and UI patterns for visualizing performance, surfacing anomalies, and explaining AI behavior—especially for multi-step agent systems • Use AI-assisted UI generation to accelerate prototyping while maintaining craft, accessibility, and consistency • Push the boundaries of what's possible when your users include both humans and machines You Might Be a Great Fit If You • Have strong frontend engineering skills (React, TypeScript) paired with design sensibility • Think deeply about interaction design, information architecture, and developer experience • Are curious about AI systems and eager to learn how agents, evaluations, and observability work • Enjoy prototyping quickly and iterating toward polish • Care about accessibility, performance, and craft • Thrive in open-source communities and async collaboration Why Arize Arize Phoenix is becoming the shared workspace where AI teams investigate issues and make decisions—while agents run evaluations, triage failures, and propose fixes alongside them. We're not just building tools for AI development. We're building the environment where humans and AI agents work together. This is a rare opportunity to define the design language for a new category of product experience. If you're excited about designing for users that include both people and AI systems, we'd love to talk. The estimated annual salary and variable compensation for this role is between $175,000 - $200,000, plus a competitive equity package. Actual compensation is determined based upon a variety of job related factors that may include: transferable work experience, skill sets, and qualifications. Total compensation