LoopNet - Software Engineer II

Visual Lease; Irvine (CA); On-site; USD 140,000 - 200,000; Full time

Job summary

CoStar Group is seeking a Software Engineer II to join our Irvine, CA team. This hybrid role combines strong C#/.NET development, AWS cloud work, and AI-assisted coding with Claude Code or GitHub Copilot to accelerate delivery and improve code quality.

The position involves architecture decisions, mentoring engineers, and building scalable backend systems across LoopNet and related brands. Join us in a modern, collaborative environment in Irvine with a four‑days‑onsite, one‑day‑remote model.

Qualifications

• Bachelor’s degree from an accredited institution.
• At least 7+ years in production with C#/.NET or .NET Core.
• Proven ability to build and launch products and meet performance SLAs.
• Strong API and backend design experience with solid software principles.
• Experience mentoring and guiding engineering teams.
• Ability to contribute to architecture decisions and coding standards.
• Hands-on testing: unit, performance, and E2E tests.

Responsibilities

• Contribute to scalable, high‑quality systems across products and brands.
• Lead architecture discussions and advocate best practices.
• Mentor engineers and help grow the team's technical capabilities.

Skills

C#/.NET

AWS

AI tools (Claude Code/GitHub Copilot)

APIs & backend

Mentoring

Architecture decisions

Unit/integration tests

Education

Bachelor’s degree

Tools

Docker

Kubernetes

Datadog

Kafka

SQL (MS SQL/MySQL)

GitHub Copilot

Claude Code

Job description

LoopNet - Software Engineer II

Job Description

CoStar Group (NASDAQ:CSGP) is a leading global provider of commercial and residential real estate information, analytics, and online marketplaces. We are seeking a highly skilled Senior Software Engineer with deep expertise in C#/.NET, AWS cloud development, and hands‑on experience with AI coding tools such as Claude Code or GitHub Copilot. In this role, you will contribute to building scalable, high‑quality systems across multiple products and brands—including LoopNet.com—while leveraging modern AI‑driven development practices to accelerate delivery and improve code quality. You will also play a key role in architecture decisions and mentoring engineers across the team.

This position is located in Irvine, CA and offers 4 days a week onsite with 1 day work from home.

BASIC QUALIFICATIONS

• ​Bachelor’s degree from an accredited, not‑for‑profit university or college.
• ​A demonstrated track record of commitment with prior employers.
• ​7+ years of production development experience with C# and .NET or .NET Core.
• ​Proven history of building and launching successful 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 a solid grasp of software design principles.
• ​Deep understanding of the business context for which you are building software.
• ​Active participation in mentoring developers and building team consensus.

PREFERRED QUALIFICATIONS

• ​Working knowledge of Vue.js or React in TypeScript.
• ​Experience with relational database design (MS SQL or MySQL), including performance tuning.
• ​Hands‑on experience with AWS services including S3, SQS, DynamoDB, and ElastiCache, as well as Apache Kafka and Datadog.
• ​Experience with microservices, distributed systems, Docker, and Kubernetes.
• ​Familiarity with CI/CD pipelines, DevOps practices, and Infrastructure as Code tools.
• ​Application security knowledge and experience with Git‑based workflows.
• ​Hands‑on professional experience with AI coding tools such as Claude Code, GitHub Copilot, or equivalent.
• ​Experience with cloud data warehouse platforms (BigQuery, Databricks, or Snowflake) and proficiency in Python for data engineering or analytics workflows.

What’s in it for You

• ​Self‑determination to drive innovative solutions.
• ​Self‑determination to improve—not mandating mandatory Mandatory Mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory mandatory 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