Senior Software Engineer

Senior Software Engineer

Job Description

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’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 a work schedule of 4 days onsite and 1 day work from home.

• 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

• 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, Cloud Watch)
• Experience building APIs and backend services
• Solid understanding of software design principles
• Experience with Git‑based workflows

• Practical experience using Claude for coding or code review
• Experience with Databricks
• Microservices or distributed systems experience
• CI/CD pipelines and Dev Ops practices
• Infrastructure‑as‑Code (Terraform, Cloud Formation, CDK)
• Experience with additional AI coding tools

• 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, Peloton, 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

Salary: $124,000 to $187,000 per year, determined by relevant skills and experience.

We welcome all qualified candidates who are currently eligible to work full‑time in the United States to apply. However, please note that CoStar Group is not able to provide visa sponsorship for this position.

CoStar Group is an Equal Employment Opportunity Employer; we maintain a drug‑free workplace and perform pre‑employment substance abuse testing. CoStar Group is a committed diverse environment and is proud to be an equal opportunity workplace and affirmative action employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or veteran status.

CoStar Group is also committed to compliance with all fair employment practices regarding citizenship and immigration status. If you are a qualified individual with a disability or a disabled veteran, you may request a reasonable accommodation if you are unable or limited in your ability to use or access  as a result of your disability. You can request reasonable accommodations by sending an email to re