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Salary
≈ $108k – $199k per year (Estimated)
Location
Hybrid (Irvine, United States)
Seniority
Senior · 6+ years exp

Confirmed on the employer's own hiring board on Oct 22, 2026. First seen by Alion on Sep 28, 2026. CoStar Group scores A on the Alion truth index.

Overview
Company
Impact
Profile match
CoStar Group is a real estate information, analytics and online marketplace company headquartered in Arlington, Virginia, behind the CoStar database and brands such as LoopNet, Apartments.com, Homes.com, Land.com, Ten-X, BizBuySell, STR, Matterport and OnTheMarket. Founded in 1987 by Andrew Florance, it is listed on NASDAQ and in the S&P 500, with major offices in Richmond, Irvine, London, Paris and Sydney serving brokers, owners, lenders, landlords and home buyers. It hires software, AI and security engineers, field researchers, account executives and sales associates, product marketers, recruiters and finance and lease administration staff.
Senior Software Engineer (C#/Databases) - Apartments.com - Irvine, CA

Job Description

CoStar Group (NASDAQ: CSGP) is a leading global provider of commercial and residential real estate information, analytics, and online marketplaces. Included in the S&P 500 Index and the NASDAQ 100, CoStar Group is on a mission to digitize the world’s real estate, empowering all people to discover properties, insights and connections that improve their businesses and lives.

We have been living and breathing the world of real estate information and online marketplaces for over 35 years, giving us the perspective to create truly unique and valuable offerings to our customers. We’ve continually refined, transformed and perfected our approach to our business, creating a language that has become standard in our industry, for our customers, and even our competitors. We continue that effort today and are always working to improve and drive innovation. This is how we deliver for our customers, our employees, and investors. By equipping the brightest minds with the best resources available, we provide an invaluable edge in real estate.

Apartments.com is the nation’s #1 rental marketplace for owners, property managers and consumers. Apartments.com is the network that millions of renters every year rely on to find their new place, is continuing to grow our industry-leading sales force. We provide apartment Property Managers and Owners with a platform to market their property listings and the industry’s most comprehensive virtual tools to attract the most and highest-quality renters. The Apartments.com Network includes Apartments.com, ForRent.com,

ApartmentFinder.com, ApartmentHomeLiving.com, and eight other leading rental sites. Our suite of services includes digital advertising, social and reputation management, and market analytic solutions which delivers innovative tools for our customers.

Learn more about Apartments.com.

Our team is seeking an accomplished Senior Software Engineer to join our team in supporting multiple software products and brands across the organization. You will have a direct impact on highly visible Apartments.com web applications that touch millions of users. You continuously learn emerging technologies and architecture advancements and apply the learnings to improve Apartments’ software products

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

RESPONSIBILITIES

  • Design and develop using Object Oriented design principles and software design patterns to attain high reusability and maintainability.
  • Deep knowledge and experience in writing unit testable software with C#
  • Develop an in-depth understanding of CoStar’s product architecture and frameworks. Maintain and contribute to CoStar’s product platform as necessary.
  • Develop database stored procedures and SQL scripts/ETL jobs that meet CoStar database standards to implement product requirements.
  • Participate and drive continuous improvement within CoStar’s Agile/Scrum teams.
  • Build consensus among different teams working on software development projects.
  • Facilitate discussions among other .NET and database developers to exchange new ideas and improvements.
  • Continually evaluate emerging technologies to identify opportunities, trends and best practices that can be used to strengthen CoStar’s technology platform and development practices.

BASIC QUALIFICATIONS

  • Bachelor’s Degree required from an accredited, not-for-profit, in-person college/university
  • A track record of commitment to prior employers
  • 6+ years of production development experience with C# .Net (or .Net Core)
  • Experience in relational database design (MS SQL or MySQL) including performance tuning
  • A demonstrable track record of building and launching successful products and platforms
  • Deliver products that meet specifications and performance SLA
  • Experienced in unit, performance, and automation testing
  • Deeply understand what drives the business for which you are building software
  • Take an active role in mentoring developers with ability to build consensus

PREFERRED QUALIFICATIONS

  • Demonstrate working knowledge Vue, React or Angular in TypeScript
  • Experience with AWS S3, SQS, Dynamo, ElastiCache, Apache Kafka and Datadog

What’s in it for You

When you join CoStar Group, you’ll experience a collaborative and innovative culture working alongside the best and brightest to empower our people and customers to succeed.

We offer you generous compensation and performance-based incentives. CoStar Group also invests in your professional and academic growth with internal training, and tuition reimbursement.

Our benefits package includes (but is not limited to):

  • Comprehensive healthcare coverage: Medical / Vision / Dental / Prescription Drug
  • Life, legal, and supplementary insurance
  • Virtual and in person mental health counseling services for individuals and family
  • Commuter and parking benefits
  • 401(K) retirement plan with matching contributions
  • Employee stock purchase plan
  • Paid time off
  • Tuition reimbursement
  • On-site fitness center and/or reimbursed fitness center membership costs (location dependent), with yoga studio, Pelotons, personal training, group exercise classes
  • Access to CoStar Group’s Diversity, Equity, & Inclusion Employee Resource Groups
  • Complimentary gourmet coffee, tea, hot chocolate, fresh fruit, and other healthy snacks

The final salary or hourly rate offered for this role will fall within the range set forth below based on a variety of factors, including but not limited to, geographic location, skills, and competencies.

Base Compensation: $124,000-$187,000 Annually

#Apartments.com

CoStar Group is an Equal Employment Opportunity Employer; we maintain a drug-free workplace and perform pre-employment substance abuse testing

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