Job Number: R0243891 AI Front-End Developer, Senior The Opportunity: GRACE is ARPA-H's production AI assistant. We've shipped the first generation of agentic AI, and now we're moving quickly to go deeper: user-built agents, multi-agent orchestration, and a platform teams can extend themselves on. We are a small, startup-minded team that ships fast and owns what we build end-to-end. We are looking for a senior front-end-leaning full-stack developer to own the experience layer of GRACE: the chat interface, the rich rendering of AI output, and the interaction patterns that make an agentic system feel trustworthy and fast. The front end is where users decide whether GRACE is reliable and worth using. You will own that surface, while operating within the privacy, security, and responsible-use requirements of our mission and the federal environment. What You’ll Work On: • Own the GRACE front end end-to-end, including the Chainlit-based chat application and the React or TypeScript components and interaction patterns layered on top of it. • Own the rendering pipeline for rich AI output, including streaming responses, markdown, code blocks, tables, citations, diagrams with Mermaid, maps with GeoJSON, and generated images, so that complex output is legible and trustworthy. • Design and build interaction patterns for agentic workflows, including tool-call progress, multi-step reasoning states, human-in-the-loop confirmations, and graceful handling of long-running or partial responses. • Apply industry best practices and emerging front-end patterns specific to agentic AI, including streaming UX, agent and tool-call visibility, and interfaces for user-built and multi-agent workflows. • Own client-side state, streaming, and real-time updates, including WebSocket or SSE, so the interface stays responsive while the backend is still working. • Build file upload, document preview, and results-display experiences for GRACE's knowledge search and research workflows. • Work close to the application layer in Python where Chainlit lives and customize rendering, session handling, and interaction behavior beyond what the framework gives you out of the box. • Partner with backend engineers on the API contract the front end consumes, shape it so it serves the user experience, and implement the glue when the boundary is fuzzy. • Implement front-end-facing integrations with GRACE's data sources and APIs, including LLM provider outputs, knowledge search, and tool results. • Write readable, tested, reviewed, and documented production-quality code across the stack. • Work hand-in-hand with our human-centered researcher and designer to turn user insights and design intent into interfaces that actually serve the user, not just approximations of the mockup. • Translate research findings and usability feedback into concrete UI changes and close the loop by shipping, measuring, and iterating. • Treat design fidelity, interaction detail, and edge-case behavior as part of the job and sweat the small things because they are what users feel. • Own front-end performance from the user's perspective, including time-to-first-token, perceived latency, and smooth streaming under real network conditions • Ensure accessibility, including Section 508 and WCAG, is built in, not bolted on. • Build front-end observability, including client-side error tracking, usage analytics, and the instrumentation needed to know what users actually do. • Rapidly prototype and iterate on new GRACE capabilities and ship, measure, and improve. • Establish and improve front-end coding standards, design review, and testing practices. • Communicate technical decisions clearly to both engineers and non-engineers. • Mentor and unblock other engineers with a bias toward ownership and speed. • Ensure strong privacy, security, and compliance in all UI, data handling, and integrations. Join us. The world can’t wait. You Have: • 7+ years of experience in software engineering, building and operating production web applications, including on the front end • 5+ years of experience designing and building for AI, LLM, chat, or agentic products, including streaming responses, citation and source display, tool-call visibility, and building for uncertain or probabilistic output • 5+ years of experience with industry best practices and front-end patterns specific to agentic AI, including streaming UX, agent and tool-call visibility, human-in-the-loop, and multi-agent workflows • 5+ years of experience with real-time UI patterns such as streaming responses, WebSockets or SSE, and optimistic or partial rendering, including web performance, cross-browser behavior, and front-end testing • Experience with TypeScript or JavaScript and React and its modern ecosystem, including hooks, state management, and component architecture • Experience in a backend language such as Python and comfort operating across the client or server boundary • Experience shipping complex, interactive UIs in high-velocity environments where you owned features end-to-end using CSS and responsive design fundamentals • Ability to communicate, give and receive feedback well, and be a self-starter with a high bar and high sense of urgency • Bachelor's degree in Computer Science Nice If You Have: • Experience with Chainlit or similar conversational or LLM front-end frameworks, including customizing rendering and interaction behavior • Experience with rich client-side rendering, including markdown, syntax highlighting, Mermaid diagrams, data visualization, or map rendering • Experience working directly with UX researchers and designers in a tight build-measure-learn loop • Experience in Microsoft Azure and within CI/CD pipelines, including deploying and operating builds • Experience with design systems and component libraries at scale • Experience in startup or early-stage environments with ambiguity, rapid iteration, and wearing multiple hats • Experience in big tech or scaled tech organizations building customer-facing products • Ability to pay strict attention to detail • Master's degree in a Computer Science related field Compensation At Booz Allen, we celebrate your contributions, provide you with opportunities and choices, and support your total well-being. Our offerings include health, life, disability, financial, and retirement benefits, as well as paid leave, professional development, tuition assistance, work-life programs, and dependent care. Our recognition awards program acknowledges employees for exceptional performance and superior demonstration of our values. Full-time and part-time employees working at least 20 hours a week on a regular basis are eligible to participate in Booz Allen’s benefit programs. Individuals that do not meet the threshold are only eligible for select offerings, not inclusive of health benefits. We encourage you to learn more about our total benefits by visiting the Resource page on our Careers site and reviewing Our Employee Benefits page. Salary at Booz Allen is determined by various factors, including but not limited to location, the individual’s particular combination of education, knowledge, skills, competencies, and experience, as well as contract-specific affordability and organizational requirements. The projected compensation range for this position is $99,000.00 to $225,000.00 (annualized USD). The estimate displayed represents the typical salary range for this position and is just one component of Booz Allen’s total compensation package for employees. This posting will close within 90 days from the Posting Date. Identity Statement As part of the hiring process, we will ask you to complete an identity verification process that leverages advanced biometrics and artificial intelligence to ensure authenticity and protect against identity fraud. You are expected to be on camera during interviews and assessments. We reserve the right to take your picture to verify your identity and prevent fraud. 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