Principal Software Engineer

Cars Commerce•Chicago, IL

About The Position

Cars Commerce is undergoing a shift to deliver a single platform that simplifies everything about buying and selling cars. We are unifying an ecosystem of automotive brands into a single, high-throughput, service-oriented platform. As a Principal Software Engineer, you will be the technical north star for the Platform Core Services team. This team owns the high-concurrency engines—Identity, Inventory, and Leads—that power a multi-billion dollar marketplace. We’re looking for a technical architect and "lead-from-the-front" builder to drive this transformation. This is a role for an engineer who wants end-to-end sovereignty over both backend systems and the product surfaces that transform data into actionable insights—from complex RBAC systems to sophisticated self-service UIs. We are an AI-first organization. We leverage Claude Code to bypass the "boilerplate tax," allowing our engineers to spend the majority of their time on high-order systems design rather than routine implementation. This is a rare opportunity: the scale of an industry leader with the velocity and intellectual freedom of a high-growth startup.

Requirements

Education: Bachelor’s degree or higher in Computer Science or equivalent industry experience.
Track Record: 12+ years of software engineering excellence, including significant time at the Staff or Principal level
Backend Mastery: Deep expertise in designing high-concurrency distributed systems. You are comfortable navigating complex data-consistency models, event-driven architectures (Kafka/MSK), and optimizing for sub-second latency.
Frontend as a System: You don’t just "build UIs"; you architect extensible frontend platforms. This means designing robust State Management strategies, implementing complex RBAC across the stack, and ensuring UI performance through efficient data-fetching patterns.
Pragmatic Polyglot: You are an expert in TypeScript/Node.js, but you are language-agnostic. You choose the tool that fits the problem, not the one that fits your comfort zone.
AI-Native: You believe AI is the biggest shift in engineering since the Cloud. You have an established workflow for leveraging LLMs to accelerate personal and team-wide output.
Strategic Advisory & Influence: You bridge the gap between technical possibility and business reality. You have a proven ability to drive consensus in complex environments by using data—not just opinion—to influence stakeholders and align engineering roadmaps with C-suite objectives.
Architectural R&D: You don’t just maintain a stack; you evolve it. You have a track record of evaluating emerging technologies (e.g., NewSQL, Edge Computing, or Agentic AI) and running proof-of-concepts that modernize the tech stack without disrupting production stability.

Nice To Haves

Experience within a large-scale, "Big Tech," or high-growth environment or FAANG, Uber, Stripe etc

Responsibilities

Architectural Stewardship: Define the evolution of our services to support sub-second latency and massive concurrency. You will bridge the gap between heavy-lift backend systems and modern, intuitive UI products.
AI Orchestration: Redefine the SDLC by integrating LLM-based orchestration into the development workflow, significantly increasing the organization’s velocity.
Influence via Data: Lead the RFC process by driving consensus across engineering and product boundaries. You don't rely on "title power"—you use data, benchmarks, and clear trade-off analysis to align stakeholders.
Operational Excellence at Scale: Own the "Four Nines" (99.99%) for services handling tens of thousands of requests per second. You will treat observability and developer experience as first-class products.
Force Multiplier: Act as a sponsor for Staff and Senior engineers. You are responsible for raising the technical "ceiling" of the entire engineering organization.