LoopNet - Software Engineer II

CoStar Group, Inc.; California (MO); On-site; USD 118,000 - 154,000; Full time

Benefits offered by this job

Health, vision, dental, and Rx

401(k) matching

Employee stock purchase plan

Paid time off

Tuition reimbursement

On-site fitness center or subsidized

Commuter benefits

On-site amenities

Job summary

CoStar Group in Irvine, CA is seeking a Senior Software Engineer with deep expertise in C#/.NET and AWS to build scalable systems across LoopNet and other products. You will influence architecture, mentor teammates, and apply AI‑driven development practices in a hybrid role (4 days onsite, 1 day remote).

You will design, develop, and deploy high‑quality back‑end services, write robust tests, and ensure performance SLAs while collaborating across teams and driving engineering excellence.

Qualifications

• Bachelor’s degree from an accredited, not-for-profit institution.
• 7+ years of production development experience with C# and .NET (or .NET Core).
• Demonstrated history of building and launching successful products and platforms.
• Experience delivering products that meet specifications and performance SLAs.
• Solid experience building APIs and back‑end systems with strong software design principles.
• Deep understanding of business context for which software is built.
• Active participation in mentoring developers and building team consensus.

Responsibilities

• Design, develop, and deploy high‑quality, scalable systems across multiple LoopNet products.
• Apply modern AI coding tools to accelerate delivery and improve code quality.
• Make key architecture decisions and enforce best practices across the engineering team.
• Mentor junior developers and foster technical consensus.
• Write robust unit, performance, and end‑to‑end tests, and maintain high code coverage.

Skills

C#/.NET

AWS

API design

Mentoring

Unit testing

Docker

Kubernetes

CI/CD

AI coding tools

Education

Bachelor’s degree

Tools

Vue.js

React with TypeScript

MS SQL

MySQL

Kafka

Datadog

Docker

Kubernetes

CI/CD

Git-based workflows

Job description

Company Overview

CoStar Group (NASDAQ:CSGP) is a leading provider of commercial and residential real estate information, analytics, and online marketplaces. LoopNet is the #1 global commercial real estate marketplace.

Position Summary

A Senior Software Engineer with deep expertise in C#/.NET and AWS cloud development, responsible for building scalable systems across LoopNet and other products. The role leverages AI‑driven development practices, participates in architecture decisions, and mentors engineering teammates. Based in Irvine, CA with a hybrid schedule (4 days onsite, 1 day remote).

Responsibilities

• Design, develop, and deploy high‑quality, scalable systems across multiple LoopNet products.
• Apply modern AI coding tools (Claude Code, GitHub Copilot) to accelerate delivery and improve code quality.
• Make key architecture decisions and enforce best practices across the engineering team.
• Mentor junior developers and foster technical consensus.
• Write robust unit, performance, and end‑to‑end tests, and maintain high code coverage.

Basic Qualifications

• Bachelor’s degree from an accredited, not‑for‑profit institution.
• 7+ years of production development experience with C# and .NET (or .NET Core).
• Demonstrated history of building and launching successful products and platforms.
• Experience delivering products that meet specifications and performance SLAs.
• Solid experience building APIs and back‑end systems with strong software design principles.
• Deep understanding of business context for which software is built.
• Active participation in mentoring developers and building team consensus.

Preferred Qualifications

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

Compensation

Base salary: $118,000–$154,000 annually. Salary is based on location, skills, and experience.

Benefits

• Comprehensive health, vision, dental, and prescription coverage.
• Life, legal, and supplemental insurance.
• Virtual and on‑site mental health counseling.
• Commuter and parking benefits.
• 401(k) retirement plan with matching contributions.
• Employee stock purchase plan.
• Paid time off.
• Tuition reimbursement.
• On‑site fitness center or reimbursed membership (location dependent).
• Employee Resource Groups.
• Complimentary healthy snacks and beverages.

EEO Statement

CoStar Group is an Equal Employment Opportunity 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. The company is committed to fair employment practices regarding citizenship and immigration status and to providing reasonable accommodations for qualified individuals with disabilities.
Applicants must be eligible to work full‑time in the United States. Visa sponsorship is not available for this role.