Senior Frontend Engineer Quality Platform Halcyon Labs

Halcyon Labs was born in 2007 when two hosts welcomed three guests to their San Francisco home, and has since grown to over 5 million hosts who have welcomed over 2 billion guest arrivals in almost every country across the globe. Every day, hosts offer unique stays and experiences that make it possible for guests to connect with communities in a more authentic way. The Community You Will Join The Quality Platform team is at the heart of Halcyon Labs's mission to deliver a seamless, high-quality experience for millions of hosts and guests. We don't just find bugs - we build the systems that prevent them. Our team sits at the intersection of Quality Engineering, Infrastructure, and Applied AI. We are evolving how software quality is built by integrating LLMs, intelligent automation, and data-driven systems into the testing lifecycle. The interfaces we build are how thousands of Halcyon Labs engineers experience that work - turning a powerful agentic testing platform into something intuitive, fast, and a pleasure to use. You will join a high-impact group of engineers who care about craft and user experience in equal measure. The Difference You Will Make As a Senior Frontend Engineer, you will build and maintain the frontend for our Quality Platform and tools - the paved path that gives Halcyon Labs engineers streamlined access to our agentic testing platform. Your primary objective will be to make complex testing and automation workflows simple to understand and effortless to act on, so engineers can validate and ship high-quality software with confidence. In this role, you will: Own the Quality Platform frontend: Design, build, and maintain the web surfaces that expose our agentic testing capabilities to engineers across Halcyon Labs. Make the agentic platform accessible: Translate sophisticated, AI-driven testing workflows into clean, intuitive interfaces that reduce friction and accelerate feedback loops. Improve developer and QE productivity: Identify UX bottlenecks in how engineers discover, run, and interpret tests, and solve them with thoughtful, well-built frontends. Partner across the stack: Work closely with backend, infrastructure, and applied-AI engineers to surface platform capabilities in the product in a coherent, scalable way. A Typical Day Collaborate with the Quality Platform, Mobile Infrastructure, Product Engineering, and Quality Engineering teams to design and develop high-quality UX. Build and maintain web UI surfaces that give engineers streamlined access to the agentic testing platform - from running and orchestrating tests to exploring results, coverage, and insights. Be an active contributor by creating high-quality, tested pull requests and reviewing others' designs and code. Build appropriate tests to ensure the reliability and performance of the software you create. Create and present your own design, product, and architecture documents, and provide feedback on others'. Visualize large amounts of data - test suites, test cases, test runs, test results, coverage, run history - in a clean, concise, and actionable fashion. Stay up-to-date with the latest trends and best practices in web development and performance engineering, and partner with applied-AI work where the UI exposes agentic capabilities. Do all this in an opinionated fashion, with humility and curiosity, as we are our own product managers. Your Expertise 5+ years of industry engineering experience. Fluency in HTML, CSS, TypeScript, React, and related web technologies. Experience with modern JavaScript libraries and tooling (e.g. React, npm, webpack). Experience building internal tooling or developer-facing UX, ideally for platforms, infrastructure, or developer/quality tooling. Expertise in visualizing large amounts of data in a clean, concise fashion. Context around Quality Engineering, testing, or automation tooling is helpful but not strictly necessary - curiosity and willingness to learn the domain matter more. Interest in or hands-on exposure to Applied AI / LLM-based systems is a plus, as you'll be building the surfaces for an agentic platform. Solid engineering and coding skills, with demonstrated knowledge of practical data structures and asynchronous programming. Strong collaboration with colleagues across multiple timezones. Strong communication and organizational skills. Ability to work in areas outside of your usual comfort zone and show motivation for personal growth without a dedicated product manager. Our Commitment To Inclusion & Belonging Halcyon Labs is committed to working with the broadest talent pool possible. We believe diverse ideas foster innovation and engagement, and allow us to attract creatively-led people, and to develop the best products, services and solutions. All qualified individuals are encouraged to apply.