Senior Backend and GraphQL Software Engineer

Job Description The Senior Engineer drives high-quality software development and innovation, serving as a key driver of technical direction within Domain’s Residential Consumer web teams. This pivotal role involves architecting scalable, highly performant user interfaces and supporting back-end systems, writing and reviewing code, and ensuring all technical solutions align with the broader Domain Strategy. Leveraging deep expertise across front and backend technology stacks the engineer will lead the development of complex features and champion frontend quality standards to solve real customer problems and enhance our website. The Senior Engineer plays a crucial role in mentoring and guiding more junior team members, fostering a culture of continuous improvement and engineering excellence. By leading by example and providing support, this role helps build a strong, cohesive squad team capable of tackling complex challenges and delivering high-quality software products. The Senior Engineer also collaborates closely within their cross- functional squad team, working closely with leaders and business analysts to ensure that software solutions are aligned with customer value and business needs. Problem-Solving and Technical Expertise Responsible for the entire lifecycle of medium-sized projects: engineering design, development, test, production, and deployment and subsequent fixes and improvements. Finds solutions to unsolved, loosely defined, highly technical problems.Consistently writes, co-writes, and reviews documentation and production-ready code that is clear, concise, tested, and easily understood by others. Proficient in multiple languages, frameworks, and tools.Quick and effective in identifying and resolving issues, balancing trade-offs between speed, quality, and technical debt. Approaches work with a security lens and actively looks for security vulnerabilities both in code and when providing code reviews. System Thinking Understands the big picture and system-wide impact, aligning with and contributes to domain- wide architecture, security and technology standards. Designs solutions with scalability and future needs in mind.Optimises for performance, maintainability, and security, actively looks for security vulnerabilities both in code and when providing code reviews.Contribute to the System Health and Tech debt backlog for their respective owned service.Collaborate with Lead Engin Mentorship and Leadership Mentors and guides junior team members, fostering a culture of continuous improvement and engineering excellence.Encourages collaboration and team alignment, ensuring the squad develops high-quality solutions.Builds a deep understanding of their product and business domain.Collaborates with Product Owners to ensure that solutions are aligned with business and customer needs. Required Experience Degree in Computer Science / Software Engineering or related fieldDeep 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 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 GraphQLAuthentication & authorization patterns in GraphQLExperience with AWS + Docker + ECS, with an understanding of platform evolution toward Kubernetes (nice-to-have) 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.DevOps practices, CI/CD, and infrastructure-as-codeStrong practical experience with cloud services technologies such as containerised deployment, DynamoDB, ElasticSearch/OpenSearchFamiliarity with containerization technologies like Docker. Experience working effectively within Agile environments.[NICE TO HAVE] Experience with C# .NET[NICE TO HAVE] Python to support our legacy services[NICE TO HAVE] Apollo Federation and/or other schema composition approaches Highly Regarded Additional Experience Hands on experience with AWSExperience with AI-assisted engineering workflowsExperience building production AI/LLM systemsAWS (or other Cloud Platform) Certification CoStar Group is an Equal Employment Opportunity Employer; we maintain a drug-free workplace and perform pre-employment substance abuse testing