Lead Software Engineer

• AI Assistant Development: You’ll build and expand McMaster.ai, our domain-expert AI assistant, and the platform that lets teammates add new Skills to it. You’ll turn McMaster’s product data and customer history into a continual learning experience that interprets intent, narrows options, explains tradeoffs, and carries context across sessions to make complex industrial work feel effortless.
• Customer Navigation: You’ll build and evolve the systems that help customers find, evaluate, and understand millions of industrial products across our digital publications, including improving search relevance with LLMs and simplifying navigation across our product offering.
• Order-to-Payment Flow: You’ll design and evolve end-to-end ordering experiences that reduce friction from checkout to mobile ordering.
• Product Merchandising: You’ll strengthen the internal platforms that power sourcing, inventory planning, receiving, and supplier relationships, helping the company make disciplined investments and scale responsibly.
• Fulfillment & Automation: You’ll lead development of software that integrates with warehouse operations, fulfillment, delivery, and customer service to reduce manual work and get orders to customers faster.

Who You Are

Our strongest engineers are curious, driven, thrive in collaborative environments, and love solving hard problems.

Software Engineering, Manufacturing, eCommerce, Customer Experience, Building Systems, Communication Skills, Technical/Engineering Design, Software Engineering, Mentoring, Technical Leadership, * 4+ years of professional full-stack or backend software engineering experience, with strong proficiency in a compiled language such as C#, Java, C++, or Rust (see our Software Engineer II role for earlier-career experience)

• Experience designing and delivering large-scale, service-oriented systems, writing maintainable, scalable code, and strengthening architecture, testing, and monitoring for reliability and performance
• Experience owning projects from early research through launch and iterative refinement, building platforms that hold up over the long run without losing sight of execution details
• A thoughtful, analytical approach to problem-solving and software design
• Strong cross-functional collaboration and communication skills, paired with a commitment to developing others through code reviews, coaching, and mentorship

Technologies We Use

• Backend: NET, .NET 10, ASP.NET Core, C#, Python
• Frontend: React, Typescript, JavaScript, CSS
• Database: MongoDB, Elasticsearch, SQL, Db2, Redis
• Testing: Selenium, Playwright, Xunit, Jest
• Infrastructure: Kubernetes, Jenkins, Gitlab, Azure, Linux, VMWare, IIS
• LLMs: OpenAI, Copilot, Claude, Gemini, Grok, perplexity, deepseek
• Applied AI: RAG, Embeddings, Vectorization, Machine Learning, Computer Vision
• Dev Tools: Swagger, Git
• Messaging /Data Streaming: Kafka, MQ

Base salary: $191,900 - $240,000

Total cash compensation typically ranges from $240,000 - $324,000, which includes annual cash profit sharing based on company profitability., Growth & Learning

• 100% tuition reimbursement
• Informal and formal mentorship
• Employee resource groups

Health & Wellbeing

• Medical, dental, pharmacy, and vision plans with no monthly premiums
• Inclusive, all-gender benefits

Time Off

• Paid time off for vacation and personal time

Family & Future

• Paid parental leave for all new parents
• Adoption and surrogacy assistance
• First-time home buyer assistance
• Industry-leading company-funded retirement accounts

McMaster-Carr is a leading e-commerce company offering products that help keep operations running smoothly, innovators designing the next generation of solutions, and makers creating and manufacturing. Our customers have trusted us for over 120 years.We earn and keep that trust by offering the right products, making them easy to find, and delivering them fast. Our industry-leading e-commerce experience, indispensable product selection, and world-class service bring hundreds of thousands of customers to McMaster.com each day.Our curious, exceptional people are at the heart of our evolution and customer experience. They turn new challenges and disruptive technologies into opportunities to refine our operations, expand our product offering, and deliver a better experience for every customer.Our Culture

We intentionally cultivate a culture focused on clear execution and long-term growth. We are responsible for building systems that endure for decades and support the company’s future. That responsibility means engineering work starts with a deep understanding of the problem and its impact, grounded in clear ownership, open communication, and direct feedback. Our teams are trusted to make thoughtful decisions about how work gets done, balancing a high bar for quality with practical execution. As an engineering leader here, you’ll have significant autonomy with end-to-end ownership, making product decisions while building things that real people interact with directly.

Our team is hybrid and comes onsite three days a week in Elmhurst, IL.

What You’ll Do

As a lead software engineer, you’ll scope and scale the systems that power McMaster-Carr’s e-commerce experience. You’ll start by learning the codebase and customer journey while shaping meaningful features. After you’ve delivered your first features, you’ll start taking on less-defined challenges where you’ll sharpen requirements and produce thoughtful, durable solutions that meaningfully improve the customers experience. Along the way, you’ll take projects from research through launch and grow into technical leadership influencing the quality of your team’s work through technical designs and mentoring the team.

Right now, we’re actively growing in the following areas