Senior Software Engineer - Backend (Java, Spring Boot)

We are looking for a motivated and hands-on Senior Software Engineer to join the CRONUS Platform Team and strengthen the Identity module for Portfolio Brands. The role will focus on building secure, reliable and scalable backend services that support customer registration, login, authentication, authorization and personal-data protection.

You will work with engineers, product managers, architects, security specialists and business stakeholders to improve Customer Identity and Access Management capabilities across Weekday, COS, ARKET and &Other Stories. You will contribute across the full development lifecycle, including design, coding, testing, deployment, monitoring and production support.

This is a long-term strategic role with strong ownership. Over time, there will be opportunities to take broader technical leadership responsibilities within the team.

WHAT YOU’LL DO

As a Senior Software Engineer, you will design and deliver secure customer identity capabilities and production-grade backend services.

Key responsibilities include:

• Design, build and maintain backend services using Java and Spring Boot.
• Develop and improve customer identity journeys, including registration, sign-in, password reset, account recovery, multi-factor authentication and social login.
• Integrate backend services with Azure AD B2C / Microsoft Entra External ID and other customer identity platforms.
• Implement secure authentication and authorization using OAuth 2.0, OpenID Connect and token-based security.
• Build reliable APIs and integrations for customer profile, consent, newsletter and related customer capabilities.
• Protect customer and personal data through secure design, access controls, privacy-aware data handling and appropriate operational controls.
• Design services for scalability, reliability, performance and maintainability.
• Improve observability through effective logging, monitoring, metrics, tracing and alerts.
• Own services across the full lifecycle, including automated testing, CI/CD, deployment, production support and continuous improvement.
• Investigate technical issues and production incidents, identify root causes and implement long-term improvements.
• Collaborate with security, architecture, product and engineering teams to turn business needs into practical technical solutions.
• Review code, support engineering standards, mentor colleagues and communicate technical risks and trade-offs clearly.
• Contribute to the future evolution of the CIAM landscape, including the adoption of new identity platforms such as Strivacity.

WHO YOU’LL WORK WITH

The CRONUS Platform Team is part of Portfolio Brands Tech and supports the digital commerce platform used by Weekday, COS, ARKET and &Other Stories. The team owns shared platform capabilities that help the brands deliver stable, secure and reliable customer experiences.

The Platform Team works across five capability areas:

• Backend Engineering: Shared backend services and system-to-system integration services.
• Site Reliability Engineering: Reliability, availability, monitoring, alerts and performance engineering.
• Automation: Quality automation using Playwright and process automation using RPA.
• Operations: Incident management, problem management and platform stability.
• Security & Compliance: Security engineering, audits and compliance.

You will work mainly within Backend Engineering and the Identity module, while collaborating closely with SRE, operations, automation, security and other product teams. The team values end-to-end ownership, open communication, shared learning and practical solutions that improve customer experience and business reliability.

WHO YOU ARE

We are looking for someone with strong backend engineering and customer identity experience, along with a collaborative and ownership-driven mindset.

• Overall Experience: 8-10 years of relevant software engineering experience, including designing, developing, testing and operating backend applications or services.
• Java: Strong and recent hands-on experience with Java 17+ and core Java concepts, including object-oriented design, collections, exception handling, concurrency and clean code.
• Spring Boot: Practical experience building production-grade REST APIs and microservices using Spring Boot and the wider Spring ecosystem.
• IAM / CIAM: Meaningful hands-on experience with customer identity and access management, including aut…