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

CoStar Group, Inc.; Irvine, Northern (CA, KY); Hybrid; USD 124,000 - 187,000; Full time

Benefits offered by this job

Healthcare coverage

Mental health support

Commuter benefits

401(k) matching

Employee stock purchase plan

Paid time off

Tuition reimbursement

On-site fitness facility

Job summary

CoStar Group in Irvine, CA is seeking a Senior Software Engineer with deep C#/.NET expertise, AWS cloud development, and hands-on AI coding tools to help build scalable, high-quality systems across LoopNet and related brands.

You will contribute to architecture decisions and mentor engineers while delivering reliable back-end services and APIs. This onsite role offers a competitive base salary and a comprehensive benefits package.

Qualifications

• Bachelor’s degree from an accredited university.
• 7+ years of production development experience with C# and .NET.
• Proven history of building and launching products and platforms.
• Experience delivering products that meet specifications and performance SLAs.
• Solid experience writing unit, performance, and automated end‑to‑end tests.
• Strong experience building APIs and backend systems with solid design principles.
• Active participation in mentoring developers and building team consensus.

Responsibilities

• Contribute to building scalable, high‑quality systems across multiple products.
• Play a key role in architecture decisions and mentoring engineers.
• Ensure delivery of reliable back‑end services and APIs.
• Collaborate with cross‑functional teams to meet performance targets.

Skills

C#

.NET

AWS

AI tools

APIs

Distributed systems

Mentoring

Education

Bachelor's degree

Tools

Docker

Kubernetes

SQL (MS SQL/MySQL)

Kafka

Datadog

CI/CD

GitHub Copilot

Claude Code

Job description

CoStar Group in Irvine, CA is seeking a Senior Software Engineer with deep C#/.NET expertise, AWS cloud development, and hands-on AI coding tools to help build scalable, high-quality systems across LoopNet and related brands.

You will contribute to architecture decisions and mentor engineers while delivering reliable back-end services and APIs. This onsite role offers a competitive base salary and a comprehensive benefits package.