Senior Engineer (Core Web)

Senior Engineer (Core Web) Job Description CoStar Group (NASDAQ: CSGP) is a leading global provider of commercial and residential real estate information, analytics, and online marketplaces. 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 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 Senior Engineer drives high-quality software development and innovation, serving as a key driver of technical direction within the Core Web Squad . This pivotal role involves architecting scalable, highly performant user interfaces, writing and reviewing code, and ensuring all technical solutions align with the broader Domain Strategy. Leveraging deep expertise in React, TypeScript, and Next.js , the engineer will lead the development of complex features, mentor junior team members, and champion frontend quality standards to solve real customer problems and enhance our website. What success looks like: 1. Technical Excellence Delivery Quality: Consistently build high-quality, scalable, and reliable solutions in collaboration with peers and Tech Leads. Deep understanding of modern web performance metrics and optimization, with experience troubleshooting and improving Core Web Vitals (INP, LCP, TTFB, and CLS) Best Practices: Champion and adopt Engineering best practices while staying current with industry trends and applying them judiciously. System Health: Actively contribute to the System Health and Technical Debt backlog, driving engineering efficiency for owned services. Cross-Domain Influence: Contribute expertise to forums like the FrontEnd Guild and Architecture Guild, collaborating with Principal Engineers on system improvements 2. Leadership and Collaboration Mentorship: Mentor Junior Engineers effectively in solution design and delivery best practices. Product Alignment: Develop a deep understanding of the product and business domain, collaborating with Product Owners and Designers to ensure solutions meet customer needs. 3. Operational Rigor System Stability: Fulfill on-call duties by responding to and resolving incidents. Proactive Maintenance: Continuously improve processes and software quality to reduce incident frequency over time, and actively maintain, update, and patch systems. Experience and Education: Core Technical Expertise Deep expertise in ReactJS, JavaScript, TypeScript, and Next.js. Strong understanding of modern architectural patterns, including Microfrontends, Single-Page Applications (SPA), and Server-Side Rendering (SSR). Deep understanding of modern web performance metrics and optimization, with experience troubleshooting and improving Core Web Vitals (INP, LCP, TTFB, and CLS) Familiarity in GraphQL, including experience adding and modifying queries and mutations. Familiarity with both Functional and Object-Oriented Programming (OOP) paradigms. Platform & Delivery Experience Hands-on experience leveraging AI coding assistants to improve engineering productivity and code quality. Experience designing software solutions built for high scale and high traffic websites. Proficiency with CI/CD pipelines (e.g., Jenkins) and Git version control. Strong practical experience with AWS cloud services, including ECS, Lambda, and CloudWatch. Familiarity with containerization technologies like Docker. Experience working effectively within Agile environments. Leadership & Collaboration Proven ability to mentor and coach more junior engineers. Experience working in cross-functional teams (collaborating effectively with Product, Design, and Technology peers). Experience collaborating with Tech Leads to optimize engineering practices and processes for team efficiency. What's Next? We'll give your application the thoughtful attention it deserves and get back to you as soon as possible. If there's a match, one of our recruitment consultants will reach out-so keep your phone handy! We're genuinely excited about the chance to work together and make a meaningful impact. Equity, Diversity & Inclusion Domain is enthusiastically and unapologetically committed to fostering an equitable, inclusive work culture which reflects our customers and communities. We are proactively looking for candidates from all lived experiences, including people with disability, and people of all ages, ethnicities, cultures (including Aboriginal and Torres Strait Islander Peoples), faiths, sexual orientations, and gender identities (including trans and non-binary people). We are committed to providing an equitable recruitment process for people with disability. If you require adjustments during the process we're here to support. If you wish to receive this job advertisement in an accessible format, or have a confidential chat about workplace adjustments, please contact our Equity, Diversity and Inclusion team at or leave a message on 1300 858 356 and we will get back to you. CoStar Group is an Equal Employment Opportunity Employer; we maintain a drug-free workplace and perform pre-employment substance abuse testing