What is a QA Engineer at Costar?
A QA Engineer at Costar plays a pivotal role in maintaining the integrity and performance of the world’s leading commercial and residential real estate information platforms. Costar manages massive, highly complex datasets and user-facing applications like Apartments.com, LoopNet, and Ten-X. In this role, you are not simply checking boxes on a test plan; you are the final line of defense ensuring that millions of real estate professionals, investors, and consumers receive accurate, real-time data and seamless digital experiences.
The impact of a QA Engineer at Costar spans across multiple engineering and product divisions. Because the business relies on high-fidelity data, your validation efforts directly influence transaction success, platform trust, and system scalability. You will be tasked with testing complex workflows, verifying database migrations, and building robust automation frameworks that accelerate development cycles while safeguarding product quality.
Working in this environment offers a unique blend of scale and technical variety. You will collaborate closely with software developers, product managers, and database specialists to tackle challenges ranging from high-traffic web performance to complex mobile application diagnostics. It is a demanding yet highly rewarding space where your technical precision and attention to detail directly shape the future of real estate technology.

