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Senior Principal Full Stack Engineer

Insight Global

Clayton, MOJobNo compensation foundPosted 1mo agoSeen in employer's feed 4 days ago

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At a glance

Compensation
No compensation found
Location
Clayton, MO
Work Authorization
Not specified

Job overview

Insight Global is hiring a Senior Principal Full Stack Engineer. The client is seeking a Principal Software Engineer to help shape an AI agent that assists users in designing and building applications on their platform. This role involves a blend of applied AI engineering and backend systems work, focusing on agent reasoning, tooling, and scalable backend services. The ideal candidate will have experience building agentic products and enjoy owning ambiguous, high-impact problems end-to-end.

Key focus areas include Design and refine how the agent interprets intent, plans multi-step work, calls tools, and recovers from failure, Build and harden the tools the agent uses to generate, run, and test applications on the client’s platform, and Develop and operate the services that power the agent in Node.js / TypeScript (Express) and Python (FastAPI).

Successful candidates bring 7+ Years Professional Software Engineering Experience and Substantial Backend Work. Important skills include TypeScript, Python, Software Engineering Fundamentals, Clean System Design, Reason About Tradeoffs Independently, and Ship Well-Tested Code. Preferred (not required): Node.js, Express, FastAPI, and Agent Reasoning & Behavior Design.

Skills & qualifications

RequiredNice to have

Skills

TypeScriptPythonSoftware Engineering FundamentalsClean System DesignReason About Tradeoffs IndependentlyShip Well-Tested CodeBackend Services Operation at ScalePerformanceReliabilityObservabilityBuilding AI- or Agent-Powered ProductsApplying LLMs to Real ProblemsProduct IntuitionSound Decision Making in AmbiguityWeigh User Needs Against Technical TradeoffsNode.jsExpressFastAPIAgent Reasoning & Behavior DesignAgent ToolingLLM IntegrationAnthropic ClaudeVertex AILiteLLMGeminiContext CachingConversation CompactionModel Context Protocol ToolingAPIs & Real-Time StreamingRESTful APIsServer-Sent EventsData ModelingMongoDBMongoosePyMongoRedisQuality & EvaluationUnit TestingIntegration TestingEnd-to-End TestingJestPlaywrightPytestCI/CDGCPAI Coding ToolsAgent FrameworksDeveloper KitsGoogle ADKLLM Tooling Ecosystem

Qualifications

7+ Years Professional Software Engineering ExperienceSubstantial Backend Work

Full job description

Job Description

Insight Global is looking for Principal Software Engineers.

Our client’s team is building an AI agent that helps users design and build applications on the client’s platform, and they’re looking for an engineer to help shape it — from how the agent reasons, plans, and recovers from failure, to the tools it uses to build and test applications, to the backend that keeps it fast and dependable at scale.

This is a blend of applied AI engineering and backend systems work, well suited to someone who has built agentic products and enjoys owning ambiguous, high-impact problems end to end. You’ll work across a TypeScript backend (Node.js / Express) and a Python (FastAPI) AI service that orchestrates the agent.

Key Responsibilities:

  • Agent reasoning & behavior — Design and refine how the agent interprets intent, plans multi-step work, calls tools, and recovers from failure — across an orchestrator and specialized builder, planner, tester, and searcher agents.

  • Agent tooling — Build and harden the tools the agent uses to generate, run, and test applications on the client’s platform, including self-healing tool retries and safe execution.

  • Backend services at scale — Develop and operate the services that power the agent in Node.js / TypeScript (Express) and Python (FastAPI), with a focus on performance, reliability, and observability.

  • LLM integration — Work with Anthropic Claude (via Vertex AI / LiteLLM) and Gemini, applying context caching, conversation compaction, and Model Context Protocol (MCP) tooling.

  • APIs & real-time streaming — Build RESTful APIs and Server-Sent Events (SSE) streams that connect the agent, the backend, and the front end.

  • Data & persistence — Model and optimize data in MongoDB (Mongoose / PyMongo), with Redis for caching and performance.

  • Quality & evaluation — Build the evaluation, instrumentation, and feedback loops that measure and improve agent quality, latency, and cost over time.

  • Testing & reliability — Write and maintain unit, integration, and end-to-end tests (Jest, Playwright, pytest) and contribute to CI/CD on Google Cloud.

We are a company committed to creating diverse and inclusive environments where people can bring their full, authentic selves to work every day. We are an equal opportunity/affirmative action employer that believes everyone matters. Qualified candidates will receive consideration for employment regardless of their race, color, ethnicity, religion, sex (including pregnancy), sexual orientation, gender identity and expression, marital status, national origin, ancestry, genetic factors, age, disability, protected veteran status, military or uniformed service member status, or any other status or characteristic protected by applicable laws, regulations, and ordinances. If you need assistance and/or a reasonable accommodation due to a disability during the application or recruiting process, please send a request to [email protected] learn more about how we collect, keep, and process your private information, please review Insight Global's Workforce Privacy Policy: https://insightglobal.com/workforce-privacy-policy/.

Skills and Requirements

  • 7+ years of professional software engineering experience, with substantial backend work.

  • Strong software engineering fundamentals — you design clean systems, reason about tradeoffs independently, and ship well-tested code that holds up in production.

  • Experience building and operating backend services at scale, with a feel for performance, reliability, and observability; proficiency in TypeScript and Python.

  • A track record of building AI- or agent-powered products, and good judgment about how to apply LLMs to real problems — what they’re good at, where they break, and how to design around both.

  • Strong product intuition — you make sound decisions in ambiguity, weigh user needs against technical tradeoffs, and know which problems are worth solving.

  • An avid user of AI coding tools, energized by exploring how AI can automate workflows, enhance creativity, and increase your personal impact. • Experience with agent frameworks or developer kits (e.g. Google ADK) and the broader LLM tooling ecosystem (MCP, CopilotKit).

  • Background in developer tools or low-code / no-code platforms.

  • Front-end development skills with TypeScript and React (React 19 / Next.js).

  • Familiarity with event-driven, real-time systems (Server-Sent Events) and high-throughput services.

  • Knowledge of web-application security best practices and OWASP principles.

  • Hands-on experience with MongoDB, Redis, and Google Cloud Platform (Vertex AI).

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