CoStar

Build scalable backend systems and provide architectural guidance and mentoring to engineers. | Bachelor's degree and over 7 years experience with C#/.NET, automated testing, and API design. | LoopNet - Senior Software Engineer 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, 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. LoopNet, the most popular place to find a space, is the #1 global commercial real estate marketplace. With more than 12 million global unique monthly visitors, LoopNet provides brokers, buyers and sellers with what they need to meet and make deals. LoopNet has established itself as the most effective and far-reaching digital marketplace for commercial real estate owners and brokers. We are not done yet! We continue to focus on driving expansion by increasing market share in the US and abroad, continuously innovating and enhancing the product and growing a powerhouse global team to reach our goals. Learn more about LoopNet. 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: 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 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 We welcome all qualified candidates who are currently eligible to work full-time in the United States to apply. However, please note that CoStar Group is not able to provide visa sponsorship for this position. #LoopNet #LI-PM3 CoStar Group is an Equal Employment Opportunity Employer; we maintain a drug-free workplace and perform pre-employment substance abuse testing

Develop and lead design of customer-facing web applications and microservices using React, TypeScript, C#, and .NET Core. | Bachelor's degree with over 6 years experience in OOP languages, distributed systems, AI adoption, C#, and CI/CD processes. | Senior Software Engineer Job Description Company Overview 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, 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. Role Overview Our team is responsible for building software in support of CoStar Group's sales teams. We think big, building innovative CRM features that empower our sales teams' success. We are a collaborative group with a mix of native mobile, data, API / platform, and front-end skills, and we are working to drive our company's future with our proprietary CRM system. We are actively hiring a Senior Software Engineer to join our Sales Development team and contribute to our AI initiatives within our CRM platform. This position is located in Richmond, VA and offers a schedule of Monday to Thursday in office and the option to work from home on Friday. Responsibilities Building customer-facing web applications using React and TypeScript. Build microservices and RESTful APIs with C# and .NET Core Drive and lead software design, developing standards and performing code reviews, resulting in robust codebases that are efficient and maintainable. Continually evaluate emerging technologies to identify opportunities, trends, and best practices that can be leveraged to strengthen CoStar’s technology platform and develop best practices. Develop comprehensive application testing procedures to ensure high-quality applications for tens of thousands of users. Basic Qualifications Bachelor’s Degree required from an accredited, not-for-profit, in-person college / university 6+ years of software development experience with OOP languages Demonstrated experience in architecting, designing and building large scale distributed, service-oriented systems and web applications in an agile environment Experience building RESTful APIs using C# Proficient understanding of code versioning tools such as Git. Understanding AI technologies and has hands-on experience in AI adoption and development. Familiarity with CI/CD deployment processes A track record of commitment to prior employers Preferred Qualifications and Skills Experience with SQL Familiarity with AWS services and tools, including but not limited to Bedrock Experience with Elasticsearch or OpenSearch Strong communication skills (to both business and technical partners) Data modeling experience from conceptual, logical and physical designs 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) Access to CoStar Group’s 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: $130,000 - $170,000 annually We welcome all qualified candidates who are currently eligible to work full-time in the United States to apply. However, please note that CoStar Group is not able to provide visa sponsorship for this position. #LI-KW1 CoStar Group is an Equal Employment Opportunity Employer; we maintain a drug-free workplace and perform pre-employment substance abuse testing

Coordinate incident response, lead security assessments, implement security tools, develop threat hunting, and mentor in forensic analysis. | Bachelor's degree, 8+ years IT with 5+ years cybersecurity, security certification (e.g., CISSP), and scripting skills. | Lead Security Engineer Job Description Overview CoStar Group is a leading global provider of commercial and residential real estate information, analytics, and online marketplaces. Included in the S&P 500 Index, 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. In this role, you'll communicate and reinforce security concepts to technical and non-technical audiences within the CoStar Enterprise. The ideal candidate will have experience implementing, using and updating standard security software in the areas of vulnerability scanning/management, leading remediation efforts, end-node security, security tool integration and orchestration for incident response. As the security section grows, so will the tools and the Lead Security Engineer will be the person charged with implementing them. The successful candidate will be a self-starter motivated to learn new technologies and tools and assist in moving security forward as it is implemented within the CoStar Enterprise. This position can be located in Arlington or Richmond, VA and is in office Monday through Thursday and work from home on Friday. Responsibilities Incident handling – serve as the incident response coordinator to oversee all incident response activities and ensure timely and successful resolution of incidents across various business verticals Develop, mature and lead incident response functions and reporting of findings Lead technical security assessments (network, application, database) for existing and newly acquired businesses or services and collaborate with other teams to adjust security configurations and architecture Facilitate quarterly incident response tabletop exercises and updating of the Incident Response Plan Team expert on Mitre Att&ck, tools, techniques, and practices of cyber attackers which you use to drive the overall strategy of the incident response team. Ability to define and develop platform automations to increase efficiency in responding to observed threats. Familiarity and comfort with at least one scripting language and basic understanding of CI/CD practices. Coordinate, performance and derive work from the security review and monitoring of the production environment setup permissions of users, open ports/services and overall network setup Ability to examine network, server, and application logs with forensic depth to determine trends and identify security incidents, and train and mentor others to deepen their skills Use security tools to audit infrastructure, detect issues and coordinate remediation of any issues Develop and mature threat hunting practices in the CoStar enterprise Collaborate with other teams to remediate discovered deficiencies, and develop and improve network and endpoint security configuration procedures Participate in 24x7 on-call rotation Basic Qualifications Bachelor’s Degree required from an accredited, not for profit university or college. A track record of commitment to prior employers One or more security certification such as SANS/GIAC, CISSP, CISM, GIAC Certified Incident Handler (GCIH), Certified Expert Incident Handler (CEIH) or equivalent 8+ years in Information Technology, with 5+ years of cyber security experience. Scripting/programming skills (Perl, Python, PowerShell) Experience with Windows Server 2012/2016 /2019 and Active Directory Preferred Qualifications and Skills Excellent oral and written communication skills to work effectively with others regardless of departmental or geographic boundaries Ability to work on a cultural diverse team that spans international time zones and foster an environment of inclusions and participation with all team members Experience with Microsoft Security tooling (Defender, Sentinel, EOP etc.) a plus Ability to produce detailed technical documentation Proficiency with PC software applications, E-Mail, and job associated applications/systems to expediently process work Requires good organization skills to produce quality work, within required specifications, and within scheduled timelines Excellent customer service skills 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 Employee Resource Groups Complimentary gourmet coffee, tea, hot chocolate, fresh fruit, and other healthy snacks We welcome all qualified candidates who are currently eligible to work full-time in the United States to apply. However, please note that CoStar Group is not able to provide visa sponsorship for this position. 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: 147,000 - 247,000 Annually #LI-AR CoStar Group is an Equal Employment Opportunity Employer; we maintain a drug-free workplace and perform pre-employment substance abuse testing