Senior Software Engineer

Senior Software Engineer Job Description **Overview:** CoStar Group (NASDAQ: CSGP) is a leading global provider of commercial and residential real estate information, analytics, and online marketplaces. Included in the S&P 500 Index, CoStar Group is on a mission to digitize the world’s real estate, empowering all people to discover properties, insights and connections that improve their businesses and lives. We have been living and breathing the world of real estate information and online marketplaces for over 35 years, giving us the perspective to create truly unique and valuable offerings to our customers. We’ve continually refined, transformed and perfected our approach to our business, creating a language that has become standard in our industry, for our customers, and even our competitors. We continue that effort today and are always working to improve and drive innovation. This is how we deliver for our customers, our employees, and investors. By equipping the brightest minds with the best resources available, we provide an invaluable edge in real estate. **Role Description:** We’re seeking a Senior Software Engineer with strong C#/.NET experience, hands-on use of Claude for AI-assisted development, and proven experience building and operating systems on AWS. This role focuses on developing scalable, cloud-native solutions while leveraging modern AI tools to accelerate development and improve code quality. This position is located **in San Diego, CA** and has the work schedule of 4 days onsite and 1 day work from home. **Responsibilities:** - Design, build, and maintain production applications using C# and .NET - Leverage Claude for code generation, refactoring, debugging, and analysis - Build and operate cloud-based solutions on AWS - Collaborate with product, architecture, and engineering teams - Participate in system design, code reviews, and technical decision-making - Improve application performance, scalability, and reliability - Mentor engineers and contribute to engineering best practices **Basic Qualifications:** - Bachelor's degree required from an accredited, not-for-profit, in-person college/university - A track record of commitment to prior employers. - Strong experience with C# and .NET / .NET Core - Hands-on AWS experience (EC2, ECS/EKS, Lambda, S3, RDS, DynamoDB, CloudWatch) - Experience building APIs and backend services - Solid understanding of software design principles - Experience with Git-based workflows **Preferred Qualifications:** - Practical experience using Claude for coding or code review - Experience with Databricks - Microservices or distributed systems experience - CI/CD pipelines and DevOps practices - Infrastructure-as-Code (Terraform, CloudFormation, CDK) - Experience with additional AI coding tools **What’s in it for you?** When you join CoStar Group, you’ll experience a collaborative and innovative culture working alongside the best and brightest to empower our people and customers to succeed. We offer you generous compensation and performance-based incentives. CoStar Group also invests in your professional and academic growth with internal training, and tuition reimbursement. Our benefits package includes (but is not limited to): - Comprehensive healthcare coverage: Medical / Vision / Dental / Prescription Drug - Life, legal, and supplementary insurance - Virtual and in person mental health counseling services for individuals and family - Commuter and parking benefits - 401(K) retirement plan with matching contributions - Employee stock purchase plan - Paid time off - Tuition reimbursement - On-site fitness center and/or reimbursed fitness center membership costs (location dependent), with yoga studio, Pelotons, personal training, group exercise classes - Access to CoStar Group’s Employee Resource Groups - Complimentary gourmet coffee, tea, hot chocolate, fresh fruit, and other healthy snacks We welcome all qualified candidates who are currently eligible to work full-time in the Unit…