Lead Software Engineer- CoStar- Arlington, VA

About the role

As CoStar’s next Lead Software Engineer, you will lead the build of a greenfield, enterprise-scale web application infused with AI, leveraging modern technologies and frontier models. Drive the development of AI-powered product experiences while shaping AI-first engineering workflows that redefine how software is built.

This is a high-impact role to architect, innovate, and influence the future of intelligent applications at scale. This position is located in Arlington, VA and is in onsite Monday – Thursday, with the option to work from home on Friday.

Responsibilities

• Arcitect scalable, resilient distributed systems — defining service boundaries, data contracts, and cross-team API standards for an enterprise-scale platform
• Build responsive, high-performance applications using React, Node.js, Tailwind, etc.
• Work with cloud-native services (Azure/AWS/GCP), containers, and microservices
• Optimize for performance, observability, and developer productivity
• Leverage AI Tooling & Automation (CI/Cd, code generation, test generation)
• Influence and establish AI-first engineering practice (vibe coding, human-in-the-loop, debugging)
• Establish AI Culture & Mentorship (team upskilling, lifecycle redefinition)
• Continually evaluate emerging technologies to identify opportunities, trends and best practices that can be used to strengthen CoStar’s technology platform and development practices

Qualifications

• Bachelor’s Degree required from an accredited, not for profit, in-person university or college. A track record of commitment to prior employers
• 8+ years of production development experience in modern technologies, like React, Vue, TypeScript, NodeJS, C#, .Net, OpenSearch, Kafka, SQL, NoSQL
• A demonstrable track record of building and launching successful products and platforms
• Experience designing for high availability, horizontal scalability, and production observability at enterprise scale
• Experience with cloud technologies like AWS, Cloud Managed Services, etc.
• Experience in Agile/Scrum processes, and Continuous delivery practices
• Experienced in unit, performance, and automation testing
• Deeply understand what drives the business for which you are building software
• Take an active role in mentoring developers with ability to build consensus

Preferred Qualifications And Skills

• Experience managing a large Enterprise level code base, code quality and dependencies
• Experience with C#, NodeJS, and/or React in particular
• Build Agents and Workflows using modern AI patterns
• Leverage Vibe coding to improve productivity and quality
• Excellent written and verbal communication skills
• Commercial Real Estate (CRE) knowledge is a bonus