Sr. Principal Software Engineer- Full Stack

At Lilly, the work is demanding because patients are waiting. We unite caring with discovery to help make life better for people around the world, knowing that every decision, every detail, and every day matters. Headquartered in Indianapolis, Indiana, our over 50,000 employees around the globe take on complex challenges to discover and deliver life-changing medicines, strengthen how health is understood and managed, and support the communities we serve. This is hard, urgent, selfless work—but it’s work worth doing. If you’re driven by purpose and ready to bring your best to work that truly matters for patients, we invite you to join us.

Purpose of the Role:

We are seeking a versatile, technically strong full-stack engineer to build and ship AI-powered platforms, developer tools, and enterprise applications within Lilly's Software Platform Engineering (SPE) organization. This is a generalist role on a small, high-leverage team that builds the platforms other teams build on—spanning knowledge graphs, AI coding infrastructure, data cataloging, and developer experience tooling.

You will work across a diverse and evolving portfolio of projects, moving fluidly between frontend development, API design, data modeling, and infrastructure depending on what the work demands. One sprint you may be standing up a Next.js application; the next you may be designing a GraphQL API backed by a Neo4j graph database; the next you may be wiring up CI/CD pipelines and deployment infrastructure on AWS/EKS. The common thread is that every project ships quickly, serves a broad internal user base, and is built with modern tooling and pragmatic engineering practices.

A defining characteristic of this role is the expectation that you use AI-assisted development tools—not as a novelty, but as a core part of how you work. You understand how to leverage tools like Claude Code, Copilot, or Cursor to dramatically accelerate delivery while maintaining code quality, and you recognize that strong computer science fundamentals are what make AI-augmented engineering powerful rather than fragile. You don't just generate code—you architect systems, validate output, and make sound engineering decisions at every layer of the stack.

This is a high-impact role for someone who thrives on variety, moves fast in ambiguous environments, and takes ownership of problems end to end. If you're energized by building something new every month, shipping it to production, and then pivoting to the next challenge—this role is for you.

Responsibilities:

Full-Stack Development & Delivery

Build and ship full-stack applications across the SPE platform portfolio, owning features end to end from problem scoping through implementation, testing, deployment, and iteration. Develop frontends, APIs, and data layers using modern technologies including Next.js, React, TypeScript, Node.js, Python, GraphQL, and Neo4j. Contribute to architecture decisions, design documents, and technical specifications for new platforms and capabilities. Ensure production quality through meaningful testing, observability, clean code practices, and disciplined version control workflows.

AI-Augmented Engineering

Use AI-assisted development tools daily as a core accelerator for design, implementation, and iteration—not as a substitute for engineering judgment. Write effective prompts, structure project context for AI tools, and critically validate AI-generated output, knowing when to trust it and when to rewrite it. Architect projects to be AI-friendly: clear module boundaries, strong documentation, well-named abstractions, and codebases that are legible to both humans and AI agents. Stay current with emerging agentic coding patterns and best practices around human-AI collaboration in software development.

Flexibility & Cross-Project Execution

Operate as a true generalist, flexing into frontend, backend, data engineering, or DevOps work depending on project needs and team priorities. Context-switch across multiple active projects and tech stacks without extended ramp-up time, delivering high-quality work in each. Collaborate with distributed teammates, product managers, and stakeholders to translate requirements into shipped software. Contribute to a team culture of rapid prototyping, knowledge sharing, and continuous improvement—leaving every codebase better than you found it.

Infrastructure & Cloud Operations

Containerize applications and services using Docker, deploy and manage them on Kubernetes (EKS), and troubleshoot production issues at the pod and cluster level—reading logs, debugging crashloops, and tracing networking problems when things go sideways. Manage deployment pipelines using Argo CD and Argo Workflows, ensuring reliable and repeatable delivery from merge to production. Navigate the AWS console when needed—whether that means investigating an IAM policy, checking EKS node health, reviewing CloudWatch logs, or configuring networking and storage resources. You don't need to be a dedicated platform engineer, but you do need to be comfortable operating in the infrastructure layer when the work requires it.

Your Basic Qualifications:

• Bachelor's degree in Computer Science, Software Engineering, or a related technical field.
• 5+ years of professional software engineering experience building and shipping production applications across frontend and backend technologies.
• Experience with computer science fundamentals—data structures, algorithms, systems design, networking, and a genuine understanding of how software works beneath the framework layer.
• Experience with modern JavaScript/TypeScript frameworks (React, Next.js) and at least one backend language (Python, Node.js, Go, or Java).
• Hands-on experience with containerization (Docker), Kubernetes, CI/CD pipelines, and cloud-native deployment on AWS or equivalent. Comfortable debugging pods, reading cluster logs, and navigating cloud consoles to troubleshoot production issues.
• Hands-on experience with relational, document, or graph database paradigms and the ability to design data models that scale.
• 1+ years of hands-on experience using AI-assisted development tools (Claude Code, GitHub Copilot, Cursor, or similar) as part of a regular engineering workflow.

What You Should Bring:

• Master's degree in Computer Science, Engineering, AI/ML, or a related field.
• 5–8+ years of professional software engineering experience, with a track record of owning and delivering complete systems—not just features—and elevating the technical capabilities of the teams around you.
• Experience with graph databases (Neo4j, property graph models) and GraphQL API design.
• Experience building developer platforms, internal tools, or infrastructure that serves other engineering teams.
• Familiarity with agentic AI architectures, LLM integration patterns, MCP (Model Context Protocol), or multi-agent orchestration.
• Experience with observability and monitoring tooling (Prometheus, Grafana, Datadog, Splunk) for production applications.
• Background in the biopharma or healthcare industry, or a strong interest in applying technology to accelerate drug discovery and patient outcomes.
• Demonstrated ability to mentor junior engineers, lead design reviews, and raise the technical bar of a team.
• Excellent communication skills—able to articulate technical tradeoffs to engineers and non-technical stakeholders with equal clarity.
• Strong work ethic and bias toward action; comfortable making decisions with incomplete information and course-correcting quickly.

What Sets You Apart:

You combine deep technical fundamentals with the ability to move fast and ship in ambiguous environments. You're equally comfortable writing a React component, debugging a Kubernetes deployment, designing a graph data model, and presenting an architecture decision to leadership. You understand that AI coding tools are a force multiplier—but only for engineers who know what good software looks like without them. You don't wait for perfect specifications—you figure out what needs to happen, build it, ship it, and iterate. You see every new project as an opportunity to learn a new domain, not a disruption to your routine. You bring an ownership mindset: if something is broken, you fix it; if something could be built, you build it.

Lilly is dedicated to helping individuals with disabilities to actively engage in the workforce, ensuring equal opportunities when vying for positions. If you require accommodation to submit a resume for a position at Lilly, please complete the accommodation request form () for further assistance. Please note this is for individuals to request an accommodation as part of the application process and any other correspondence will not receive a response.

Lilly is proud to be an EEO Employer and does not discriminate on the basis of age, race, color, religion, gender identity, sex, gender expression, sexual orientation, genetic information, ancestry, national origin, protected veteran status, disability, or any other legally protected status.

Our employee resource groups (ERGs) offer strong support networks for their members and are open to all employees. Our current groups include: Africa, Middle East, Central Asia (AMECA), Black Employees at Lilly (BE@Lilly), Chinese Culture Network (CCN), EnAble, Evolve, Lilly Indian Network (LIN), Organization of Latinx at Lilly (OLA), Pride (LGBTQ+ Allies), Veterans Leadership Network (VLN) and Women’s Initiative for Leading at Lilly (WILL).

Actual compensation will depend on a candidate’s education, experience, skills, and geographic location. The anticipated wage for this position is

$129,000 - $211,200

Full-time equivalent employees also will be eligible for a company bonus (depending, in part, on company and individual performance). In addition, Lilly offers a comprehensive benefit program to eligible employees, including eligibility to participate in a company-sponsored 401(k); pension; vacation benefits; eligibility for medical, dental, vision and prescription drug benefits; flexible benefits (e.g., healthcare and/or dependent day care flexible spending accounts); life insurance and death benefits; certain time off and leave of absence benefits; and well-being benefits (e.g., employee assistance program, fitness benefits, and employee clubs and activities).Lilly reserves the right to amend, modify, or terminate its compensation and benefit programs in its sole discretion and Lilly’s compensation practices and guidelines will apply regarding the details of any promotion or transfer of Lilly employees.

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