Senior Core Web Engineer (React/Next.js)

CoStar Group; Sydney; On-site; AUD 140,000 - 190,000; Full time

Benefits offered by this job

Extra days of annual leave

Leadership development programs

LinkedIn Learning

Perkbox discounts

Job summary

CoStar Group's Domain in Sydney seeks a Senior Engineer (Core Web) to lead frontend architecture and deliver scalable web applications. You will drive performance optimisations, mentor engineers, and collaborate with Product and Design to ship customer-centric features.

The role combines hands-on coding with technical leadership, focusing on robustness, security, and maintainability in a fast-paced, inclusive environment. Strong expertise in React/Next.js is essential.

Qualifications

• Degree in Computer Science, Software Engineering, or a related discipline.
• Strong expertise in modern frontend technologies, including React, JavaScript, TypeScript, and Next.js.
• Experience building scalable, high-traffic web applications using modern architectural patterns such as Micro Frontends, SPA, and SSR.
• Experience working with GraphQL, cloud-native technologies (AWS), containerisation (Docker), and modern CI/CD practices.
• Proficiency in designing and delivering high-quality software solutions within Agile development environments.
• Collaborative mindset with proven experience working across Product, Design, and Engineering teams to deliver customer-focused outcomes.
• Demonstrated ability to mentor junior engineers, contribute to engineering best practices, and drive continuous improvement within development teams.
• Security: Familiarity with modern Application Security Practices (OWASP) preferred.
• Deep understanding of web performance optimisation, including Core Web Vitals (INP, LCP, CLS, and TTFB).

Responsibilities

• Build high-quality, scalable, and reliable solutions, applying modern engineering best practices and contributing to continuous improvement across the technology landscape.
• Demonstrate strong expertise in web performance optimisation, including Core Web Vitals (LCP, INP, CLS, and TTFB), with a focus on delivering exceptional customer experiences.
• Contribute to the health, stability, and evolution of platforms by addressing technical debt, improving system performance, and influencing engineering standards through collaboration with broader technical communities.
• Mentor and support junior engineers, while partnering closely with Product Managers and Designers to deliver customer-centric outcomes aligned with business goals.
• Take ownership of operational excellence, including participating in on-call rotations, responding to incidents, and proactively improving system reliability, security, and maintainability.

Skills

React

JavaScript

TypeScript

Next.js

Web performance optimization

Agile development

Mentoring

Cross-functional collaboration

OWASP security awareness

Education

Degree in Computer Science, Software Engineering, or a related discipline

Tools

Docker

AWS

CI/CD

GraphQL

Job description

CoStar Group's Domain in Sydney seeks a Senior Engineer (Core Web) to lead frontend architecture and deliver scalable web applications. You will drive performance optimisations, mentor engineers, and collaborate with Product and Design to ship customer-centric features.

The role combines hands-on coding with technical leadership, focusing on robustness, security, and maintainability in a fast-paced, inclusive environment. Strong expertise in React/Next.js is essential.