Senior Software Engineer - AI-Driven .NET on AWS (Hybrid)

CoStar Group, Inc.; Irvine (CA); On-site; USD 124,000 - 187,000; Full time

Benefits offered by this job

401(K) retirement plan with matching

Employee stock purchase plan

Paid time off

Tuition reimbursement

On-site fitness center

Job summary

CoStar Group, Inc. is seeking a Senior Software Engineer for LoopNet in Irvine, CA. The role focuses on C#/.NET, AWS cloud development, and AI coding tools to accelerate delivery while maintaining high quality.

You will help shape architecture, mentor engineers, and contribute to scalable platforms across LoopNet and related brands. This position offers four days onsite and one day remote, with strong emphasis on collaboration and innovation.

Qualifications

• Bachelor’s degree from an accredited university.
• 6+ years of production development experience with C# and .NET.
• Experience building APIs and backend systems.
• Experience delivering products that meet specs and SLAs.
• Strong skills in unit, performance, and automated end-to-end testing.
• Mentoring and contributing to team decisions and growth.

Responsibilities

• Build scalable, high‑quality systems across multiple products and brands.
• Contribute to architecture decisions and mentoring engineers across the team.

Skills

C#/.NET

APIs & Backend Systems

Software Architecture

Mentoring & Leadership

Quality & Testing

Cloud Development (AWS)

Education

Bachelor’s degree

Tools

AWS: S3/SQS/DynamoDB/ElastiCache

Docker

Kubernetes

Apache Kafka

Datadog

Git-based Workflows

Claude Code / GitHub Copilot

Job description

CoStar Group, Inc. is seeking a Senior Software Engineer for LoopNet in Irvine, CA. The role focuses on C#/.NET, AWS cloud development, and AI coding tools to accelerate delivery while maintaining high quality.

You will help shape architecture, mentor engineers, and contribute to scalable platforms across LoopNet and related brands. This position offers four days onsite and one day remote, with strong emphasis on collaboration and innovation.