Full Stack Python Engineer

The Health and Services Operation of Leidos is seeking a Full Stack Python Engineer to support a Critical Health programCandidates MUST: Be US Citizen or Green Card holders with the ability to obtain a level 5 Public Trust ClearanceANDBe currently located in the UNITED STATES for the current three consecutive years.Role is a telecommuting role.The GRACE team builds and operates the agency's purpose-built AI assistant — a production system used daily by all ARPA-H staff to accelerate healthcare research, program launches, and agency operations. GRACE is a Python-first, full-stack platform built on Chainlit, integrating OpenAI GPT, Anthropic Claude, and Google Gemini models with real-time streaming interfaces, custom Mermaid diagram rendering, GeoJSON map generation, Slack channel search, SharePoint document indexing, and external API connections, all running on Azure in a FedRAMP-aligned environment.We are hiring a Full Stack Software Development Engineer to backfill a critical seat. You will work on the full vertical: Chainlit application layer, custom component development, Python backend services, API integrations, and production operations.This is not a role where front-end and backend are handed off between people. You own both. You ship both.We ship on a weekly cadence. We hold a <4-hour SLA for issue response. The bar is high and the mission is real. We operate with a product-led, customer-obsessed culture and a bias for shipping over planning.Key Job ResponsibilitiesFull Stack Application Development (Chainlit + Python Backend)Own the GRACE application layer end-to-end — Chainlit lifecycle hooks, chat profiles, session management, streaming configuration, data persistence, and human feedback integrationBuild and extend custom Chainlit components in React/TypeScript for advanced rendering surfaces: Mermaid v11 diagrams, GeoJSON/OpenStreetMaps, Imagen4 image outputs, and multi-model conversation stateDesign, build, and maintain Python backend services and API integrations powering GRACE's tool-calling architecture: internal document search (SharePoint/vector search), Dimensions API (, Google Search, Slack channel history, and Imagen4 image generationOwn the Entra ID OAuth 2.0/OIDC authentication integration within Chainlit, ensuring seamless and secure SSO flowsDesign and maintain secure file handling pipelines all type types — validation, sanitization, storage, and retrievalBuild and maintain multi-LLM routing logic across OpenAI GPT, Anthropic Claude, and Google Gemini — including model switching, streaming completions, tool-call orchestration, and fallback handlingCustomization & Front-End ExtensionExtend Chainlit's front-end via CSS/JS customization, Write custom React components where Chainlit's native rendering falls short — Mermaid v11 is a live example of this; you will own and evolve itEnsure all rendering surfaces meet accessibility standardsCollaboration & Customer ObsessionWork directly with the GRACE product team and ARPA-H stakeholders to translate user feedback into shipped improvements on a weekly cadenceLead code reviews, set engineering standards, and mentor teammatesContribute to architecture decisions, technical documentation, and internal engineering wikisBasic QualificationsBachelor's degree in computer science or data science7+ years of non-internship professional software development experience7+ years of Python as a primary programming language in production environments7+ years of leading design or architecture (design patterns, reliability and scaling) of new and existing systems experienceExperience building and shipping production LLM/AI chat applications — streaming, tool-calling, multi-turn conversation state managementExperience with Chainlit or a comparable Python-first conversational AI framework (Streamlit, Gradio, or equivalent) in a production contextExperience building and owning REST APIs and backend service integrations end-to-endExperience with OAuth 2.0 / OIDC authentication flows in production systemsExperience with cloud infrastructure (Azure preferred) and containerization (Docker)Experience with modern JavaScript/TypeScript tooling and frameworksExperience working with relational databases (eg PostgreSQL), including schema design and writing efficient queries.Experience as a mentor, tech lead, or leading an engineering teamPreferred Qualifications7+ years of full software development life cycle, including coding standards, code reviews, source control management, build processes, testing, and operations experienceChainlit-specific experience: custom component development, Experience writing custom React/TypeScript components and managing application state (eg Recoil, Redux, or similar)Experience with a modern UI frameworks and styling approaches (MUI, Tailwind, or similar)Experience with multi-LLM API integration (OpenAI, Anthropic Claude, Google Gemini) including streaming completions and tool-call orchestrationExperience with vector databases and semantic