Senior Software Engineer

CoStar Group•San Diego, CA

14h•Hybrid

About The Position

CoStar Group is seeking a Senior Software Engineer with strong C#/.NET experience, hands-on use of Claude for AI-assisted development, and experience building and operating systems on AWS. The role develops scalable, cloud-native solutions while using modern AI tools to accelerate development and improve code quality. The position is based in San Diego, California, with four days onsite and one day working from home each week.

Requirements

Bachelor's degree from an accredited, not-for-profit, in-person college or university.
A track record of commitment to prior employers.
Strong experience with C# and .NET/.NET Core.
Hands-on AWS experience, including EC2, ECS/EKS, Lambda, S3, RDS, DynamoDB, and CloudWatch.
Experience building APIs and backend services.
Solid understanding of software design principles.
Experience with Git-based workflows.
Must be currently eligible to work full-time in the United States; visa sponsorship is not available.

Nice To Haves

Practical experience using Claude for coding or code review.
Experience with Databricks.
Microservices or distributed systems experience.
Experience with CI/CD pipelines and DevOps practices.
Experience with Infrastructure-as-Code tools such as Terraform, CloudFormation, or CDK.
Experience with additional AI coding tools.

Responsibilities

Design, build, and maintain production applications using C# and .NET.
Use 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.

Benefits

Generous compensation and performance-based incentives.
Professional and academic development through internal training.
Tuition reimbursement.
Comprehensive medical, vision, dental, and prescription drug coverage.
Life, legal, and supplementary insurance.
Virtual and in-person mental health counseling services for individuals and families.
Commuter and parking benefits.
401(k) retirement plan with matching contributions.
Employee stock purchase plan.
Paid time off.
On-site fitness center and/or reimbursed fitness center membership costs, depending on location; facilities and offerings may include a yoga studio, Pelotons, personal training, and group exercise classes.
Access to Employee Resource Groups.
Complimentary gourmet coffee, tea, hot chocolate, fresh fruit, and other healthy snacks.