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 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.

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 information, analytics, online marketplaces and +3D digital twin technology. Together, Domain and CoStar Group is dedicated to digitising the world’s real estate, empowering all people to discover properties, insights, and connections that improve their businesses and lives.

The role of a Senior Software Engineer is pivotal in supporting the delivery of our Domain Strategy by driving innovation and ensuring the development of high-quality software solutions. By leveraging advanced technical skills and a deep understanding of software engineering principles, the Senior Software Engineer contributes to the creation of robust, scalable, and efficient software platforms and services that enable teams to deliver customer value quickly and safely.

This role supports our strategy by building and evolving foundational engineering capabilities that power key experiences across our digital channels.

 The Senior Software Engineer helps ensure these foundations are reliable, well-designed, and easy to consume—so product teams can focus on solving customer problems rather than rebuilding common patterns. This includes shaping APIs and integration layers, improving system performance and resilience, and ensuring strong engineering practices across delivery.

In addition to hands-on engineering, the Senior Software Engineer plays a crucial role in mentoring and guiding other engineers, fostering a culture of continuous improvement and engineering excellence. Through high-quality code, thoughtful reviews, and pragmatic architectural leadership, the role uplifts team capability and strengthens our ability to deliver high-impact outcomes.

The Senior Software Engineer also contributes to operational and delivery excellence by taking ownership of the systems they build, participating in supporting production services when required, and driving improvements that reduce operational toil. By investing in automation, observability, testing, and developer experience, this role helps the organisation deliver more predictably, operate more safely, and scale effectively.

By staying abreast of industry trends and applying modern best practices, the Senior Software Engineer ensures our engineering approaches remain fit-for-purpose, adaptable, and aligned to long-term business needs—turning strategy into sustainable, high-quality software outcomes

What success looks like

Technical Excellence and Innovation

• Build high quality scalable, reliable and performant solutions in collaboration with other engineers and tech leads.
• Keep abreast of latest trends in technology and software engineering. Use responsible engineering principles to understand when and how to apply those same trends.
• Champion and adopt Engineering best practices.
• Participate in and contribute to cross-domain technology forums such as Architecture Guild and Tech Leadership Guild.
• Contribute to the System Health and Tech debt backlog for their respective owned service.
• Champion engineering efficiency for their respective team and services.
• Collaborate with Lead Engineers and Tech Leads on improving process and system change.

Leadership and Collaboration

• Mentor more Junior Engineers in Solution design and building high-quality solutions.
• Build a deep understanding of their product and business domain.
• Collaborate with Product Managers to ensure that solutions are aligned with business and customer needs

Operations

• Be on-call and respond to incidents when raised.
• Continuously find ways to improve process and quality of software to reduce incidents over time.
• Maintain, update and patch systems as and when required.

Experience:

• Experience designing and delivering software solutions for scale, reliability, and maintainability
• Experience supporting highly trafficked customer-facing web platforms and/or complex mobile apps
• Experience partnering with Tech Leads/Engineering Leads to improve engineering practices, delivery processes, and platform maturity
• Experience working with common cloud platforms such as AWS (preferred)
• Experience implementing DevOps practices including CI/CD, automation, and infrastructure-aware development
• Experience working in Agile environments and collaborating through iterative delivery
• Experience mentoring and coaching more junior engineers through pairing, code reviews, and technical guidance
• Experience working in cross-functional teams (Product, Design, Engineering, Analytics, etc.)
• Experience designing, building, and operating microservices-based and/or distributed systems
• Experience with both relational and non-relational databases and making pragmatic trade-offs (e.g., performance, consistency, cost)
• Experience with AI toolings and can leverage them to help with day to day tasks

Technical Skills

• Deep expertise in at least one programming language and stack, with strong preference for Node.js / TypeScript in backend systems
• Strong experience designing and operating GraphQL APIs (schema design, resolvers, performance, caching, observability, versioning/deprecation)
• Experience with Apollo GraphQL (Apollo Server and related tooling); Apollo Federation is a nice-to-have
• Strong understanding of synchronous and asynchronous integration patterns (REST/GraphQL APIs, events/messaging)
• Experience applying shift-left testing in practice (unit, integration, contract, and end-to-end testing), and knowing where each adds value
• Familiarity with modern software design principles (functional and object-oriented approaches), and applying them appropriately in TypeScript
• Familiarity with document and relational persistence models and data access patterns
• Familiarity with cloud design patterns and distributed systems concepts (timeouts, retries, backpressure, idempotency, rate limiting, circuit breakers)
• Demonstrated experience applying modern engineering practices (testing discipline, CI/CD, operational ownership, security) in previous roles

Platform / Infrastructure (AWS, Containers, CI/CD)

• Experience building and operating services on AWS
• Experience with Docker and containerised workloads
• Experience deploying and operating services on ECS; experience with or exposure to Kubernetes is a nice-to-have (as we move in that direction)
• Experience with CI/CD pipelines and release automation; experience with Jenkins is preferred
• Experience implementing observability practices (structured logging, metrics, tracing, alerting) and participating in on-call/operational support

Education and Certifications

• [BONUS] AWS (or other cloud platform) certification

Team / Domain Specific (Experience Foundations / GraphQL Platform)

• Strong experience with TypeScript services supporting frontend consumers (Web and App)
• Experience operating a GraphQL platform used by multiple teams/consumers, with a focus on reliability, performance, and developer experience
• Familiar with GraphQL frameworks such as Yoga, Apollo (Preferred)
• Experience with query cost analysis, rate limiting, depth limiting in GraphQL
• Authentication & authorization patterns in GraphQL
• Experience with AWS + Docker + ECS, with an understanding of platform evolution toward Kubernetes (nice-to-have)
• [NICE TO HAVE] Python to support our legacy services
• [NICE TO HAVE] Apollo Federation and/or other schema composition approaches

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