UI Engineer - Full-Stack (React/TypeScript, Python)

About The RoleWe are building the control plane for AI agents in teams and companies.As a UI Engineer, you'll help build the user-facing layer of that control plane - the web applications, workflows, and interfaces that make powerful agent infrastructure usable by real teams. You'll work alongside another senior UI engineer, with real ownership over specific surfaces and problems rather than sole responsibility for the whole frontend. Your core craft is React and TypeScript: component architecture, state management, performance, and the judgment to turn complex systems into interfaces people trust.Our designers aren't just handing off mockups - several of them now build UI directly, using coding agents to write real production code. A big part of this role is partnering with them: helping them realize their design intent, reviewing and hardening what they ship, and bringing software engineering discipline — architecture, performance, testing, maintainability - to the frontend as it grows. You won't own visual design; that's their job. You'll help ensure the engineering quality of what ends up in production.You'll also work with our Python backend - reading and extending services, shaping APIs, and making sure the frontend and backend evolve together.You'll also help define a new interface paradigm: agents as an interactive modality - not just chat, but structured, controllable, and production-grade workflows.If you love deep frontend craft, enjoy raising the bar on code quality without gatekeeping who gets to write it, want full-stack range without carrying backend architecture solo, and care about how humans interact with autonomous systems - we want to talk.What You'll OwnWeb Application & Product Experience (primary Focus)Help shape the architecture and implementation of our React + TypeScript web application, alongside our other senior UI engineerBuild high-performance, stateful interfaces for managing agentsDevelop dashboards, policy configuration UIs, audit views, and workflow buildersEstablish frontend patterns, component structure, and state management conventions the whole team - including designers - can build onOwn specific surfaces end-to-end, from first pass to productionBackend & API WorkExtend and maintain Python backend services that support the UIDesign or shape APIs for agent control, policy configuration, and observabilityWork within a Kubernetes-native, cloud-based distributed systemCollaborate on schema design and data modeling where it affects the frontend experienceAgent-Native InterfacesExplore agents as a new user interface modalityDesign structured, interactive agent workflows beyond simple chatCombine UI controls with agent reasoningExperiment with hybrid patterns: visual + conversational + automated systemsCLI & Future InterfacesContribute to a TypeScript- or Python-based CLIDesign consistent interaction patterns across web and CLILay groundwork for potential future mobile interfacesDesign Engineering & CollaborationPartner directly with designers as they build UI using coding agents — pairing, reviewing, and unblocking themReview and refactor designer-written code to meet engineering standards for architecture, performance, and maintainabilityHelp designers translate design intent into robust, production-ready code rather than one-off prototypesKnow when to harden code for production and when a good-enough prototype is the right callWork closely with product and design to translate concepts into shipped software, and iterate quickly based on feedbackWhat We're Looking ForStrong FitDeep experience building production-grade web applications in React + TypeScript - component architecture, state management, performanceComfortable reviewing, refactoring, and building on code written by others - including designers using AI coding tools - without being precious about who wrote itComfortable working in a Python backend: reading, extending, and occasionally designing services and APIsStrong eye for interaction design and interface quality (we have designers for visual design - but you should have good taste)Experience shipping SaaS products used by technical teamsAbility to translate complex backend systems into usable interfacesStrong API design instinctsBonusExperience with design systems or component librariesExperience building developer tools or control-plane softwareExperience designing workflow builders or configuration-heavy interfacesExperience with real-time systems or streaming UIsExperience building CLIsFamiliarity with LLM-powered products or agent systemsDeeper distributed-systems or Kubernetes experienceWhat Makes This Role UniqueYou'll help define how teams interact with autonomous agents. You'll build interfaces for infrastructure-level systems, with full-stack range when you need it. You'll operate at the intersection of product design, distributed systems, and AI. You'll own specific surfaces end-to-end, from concept to production, as part of a small, senior UI team. This is a high-impact, high-autonomy role. You'll influence product direction and user experience at this early stage of the company.Who Thrives HereEngineers who love frontend craft and want to see it shape a whole product. People who enjoy pairing with designers and helping non-engineers ship better code, not just working alongside other engineers. Builders who are comfortable dipping into Python and backend systems when needed, without wanting to own them. People who are comfortable turning complexity into usable abstractions. Those excited about inventing new human-AI interaction models. Highly collaborative people who thrive working as part of a team. People who thrive in early-stage startup environments - high ambiguity, fast iteration, done is better than perfect. If you want to build the interface layer for the agent-native era - let's talk.Compensation Range: $140K - $320K