AI Front-End Developer, Senior

Booz Allen Hamilton•Washington, DC

1d•$99,000 - $225,000•Remote

About The Position

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.

Requirements

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 To Haves

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

Responsibilities

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.