Senior Front End Developer (#26-118) in Arlington, Virginia at Strategic Analysis, Inc.

Strategic Analysis, Inc. (SA) Is seeking a Senior Front End Software Developer for the Advanced Research Projects Agency for Health (ARPA-H)

Overview:

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. 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.

Responsibilities:

Own the Front-End Experience
• Own the GRACE front end end-to-end: the Chainlit-based chat application and the React/TypeScript components and interaction patterns layered on top of it
• Own the rendering pipeline for rich AI output: streaming responses, markdown, code blocks, tables, citations, diagrams (Mermaid), maps (GeoJSON), and generated images, so that complex output is legible and trustworthy
• Design and build interaction patterns for agentic workflows: 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: 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 (WebSocket/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 Across the Stack
Work close to the application layer in Python where Chainlit lives; 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 production-quality code across the stack: readable, tested, reviewed, and documented

Partner with a human-centered designer and own quality, performance and accessibility

Requirements:

• Bachelor's or Master's in Computer Science, a related field, or equivalent practical experience
• 7+ years of professional software engineering experience building and operating production web applications, with a primary focus on the front end
• Experience designing and building for AI, LLM, chat, or agentic products: streaming responses, citation and source display, tool-call visibility, and building for uncertain or probabilistic output
• Working knowledge of industry best practices and front-end patterns specific to agentic AI (streaming UX, agent and tool-call visibility, human-in-the-loop, multi-agent workflows)
• Strong proficiency in TypeScript/JavaScript and deep, hands-on expertise with React and its modern ecosystem (hooks, state management, component architecture)
• Working proficiency in at least one backend language (Python strongly preferred, given Chainlit) and comfort operating across the client/server boundary
• Proven experience shipping complex, interactive UIs in high-velocity environments where you owned features end-to-end
• Strong CSS and responsive design fundamentals
• Experience with real-time UI patterns: streaming responses, WebSockets or SSE, and optimistic/partial rendering
• Solid understanding of web performance, cross-browser behavior, and front-end testing
• Strong attention to detail and a high bar for code quality; you care about how it looks, how it feels, and how it reads six months later
• Clear, direct communicator who gives and receives feedback well and makes the people around them better

Preferred Qualifications

•Hands-on experience with Chainlit or similar conversational/LLM front-end frameworks, including customizing rendering and interaction behavior
• Experience with rich client-side rendering: 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 on Microsoft Azure and within CI/CD pipelines; comfort deploying and operating what you build
• Familiarity with design systems and component libraries at scale
• Track record in startup or early-stage environments: comfort with ambiguity, rapid iteration, and wearing multiple hats
• Experience in big tech or scaled tech organizations building customer-facing products

Education: Bachelor's or master's degree in computer science, Software Engineering, or a related field, or equivalent practical experience
Location: Remote with occasional travel
Clearance: Ability to obtain HHS Public Trust.