Senior Software Engineer - Backend/GraphQL

CoStar Group, Inc.; Sydney; On-site; AUD 130,000 - 170,000; Full time

Job summary

CoStar Group, Inc. is seeking a Senior Engineer to drive high-quality software development across our Residential Consumer web teams.

You will architect scalable user interfaces and supporting back-end systems, lead complex feature development, and mentor junior engineers to uphold engineering excellence. In this role, you will work with Node.js/TypeScript, GraphQL, Apollo, AWS, Docker, and CI/CD practices to deliver high-traffic web solutions.

Qualifications

• Degree in Computer Science / Software Engineering or related field.
• 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).
• 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 GraphQL.
• Authentication & authorization patterns in GraphQL.
• Experience 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
• Experience designing software solutions built for high scale and high traffic websites.
• DevOps practices, CI/CD, and infrastructure-as-code
• Strong practical experience with cloud services technologies such as containerised deployment, DynamoDB, ElasticSearch/OpenSearch
• Familiarity 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
• Hands on experience with AWS
• Experience with AI-assisted engineering workflows
• AWS (or other Cloud Platform) Certification

Responsibilities

• Own the entire lifecycle of medium-to-large features: design, development, testing, production, and enhancements.
• Architect scalable, high-performance frontend and backend components.
• Lead code reviews and maintain high standards of code quality and security.
• Mentor junior engineers and foster a culture of continuous improvement.
• Collaborate with product owners and cross-functional teams to deliver customer-focused solutions.
• Ensure reliability, performance, and security across GraphQL services and integrations.

Skills

Node.js

TypeScript

GraphQL

Apollo GraphQL

REST

AWS

Docker

ECS

Kubernetes (nice-to-have)

CI/CD

DynamoDB

ElasticSearch/OpenSearch

DevOps

Python (nice-to-have)

C# .NET (nice-to-have)

AI-assisted coding

Tools

AWS tooling

GraphQL tooling

Apollo Server

Docker

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 field
• 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,
• 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 GraphQL
• Authentication & authorization patterns in GraphQL
• Experience 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
• Experience designing software solutions built for high scale and high traffic websites.
• DevOps practices, CI/CD, and infrastructure-as-code
• Strong practical experience with cloud services technologies such as containerised deployment, DynamoDB, ElasticSearch/OpenSearch
• Familiarity 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
• Hands on experience with AWS
• Experience with AI-assisted engineering workflows
• AWS (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