Senior Engineer

Senior Engineer Job Description Technical Excellence & Innovation Build high-quality, scalable, reliable, and performant solutions with engineers and tech leads. Champion engineering best practices and contribute to system health and technical debt improvements. Drive engineering efficiency and collaborate with tech leads to improve processes and systems. Leadership & Collaboration Mentor junior engineers in solution design and development. Develop a strong understanding of the product and business domain. Work with Product Managers to ensure solutions meet customer and business needs. Operations Participate in on-call rotations and respond to incidents. Continuously improve processes and software quality to reduce incidents.

Designing scalable software, high-traffic websites, and complex mobile apps. Working with Tech Leads to optimize engineering practices. Cloud platforms (AWS, Azure, GCP), DevOps, CI/CD, Agile. Mentoring junior engineers and collaborating with cross-functional teams. Microservices architecture and relational/non-relational databases.   Technical Skills Deep expertise in at least one of: Node.js (TypeScript), React (TypeScript), or Python — and comfortable across all three Working knowledge of .NET (C# preferred) — you don't need to be an expert, but you can read, review, and contribute to .NET codebases when needed Strong understanding of REST API design, security best practices, and authentication patterns (JWT, OAuth2, JWKS) Extensive experience with relational databases (PostgreSQL) — including schema design, query optimization, and migrations Proven ability to apply Clean Architecture or similar structured design patterns in a production codebase Strong experience with AWS (EC2, SQS, S3, CloudFront) and cloud-native patterns Experience designing and working with asynchronous/event-driven systems (message queues, background workers) Track record of delivering high-quality features in an Agile environment using Git, CI/CD, Jira, and Confluence   Nice-to-have skills:  Experience with Auth0 or enterprise identity providers (SSO, M2M, multi-tenant auth) Experience with observability tooling — New Relic, Mixpanel, CloudWatch A security-first mindset — input validation, token verification, least privilege, avoiding common OWASP vulnerabilities Experience leading or significantly contributing to a platform migration or re-architecture Familiarity with containerisation (Docker) and Kubernetes or Helm deployments Education & Certifications Degree in Computer Science/Software Engineering. Bonus: AWS or other cloud certification. Company 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 and the, 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. About Domain: Domain is a leading property technology and services marketplace that is home to one of the largest portfolios of property brands in Australia, including the Domain, Allhomes and Commercial Real Estate (CRE) platforms. In 2025, Domain became part of CoStar Group (NASDAQ: CSGP), a global leader in commercial real estate