Senior Full-Stack Software Engineer with OAuth

About the Role

As a Senior Full Stack Software Engineer, you will join an experienced cross-functional engineering team responsible for designing, developing and evolving the Authentication and Authorization capability used across multiple products and engineering teams.

This is not a traditional application development role. You will help build a reusable identity platform that enables other engineering teams to adopt standardised authentication and authorisation services while improving security, developer experience and operational efficiency.

The capability provides shared identity and access management services that help applications authenticate users securely, authorise access to business resources and integrate with enterprise identity providers.

Built on Auth0, Fine-Grained Authorization (FGA) and modern Azure services, it includes reusable SDKs, reverse proxy services and developer tooling that make secure integration simpler across the technology landscape.

You will work closely with architects, product teams, platform engineers and business stakeholders to deliver secure, scalable and high-quality technology solutions. You will be expected to work with a high degree of autonomy, take ownership of significant work packages and make sound technical decisions within the agreed platform direction.

What Success Looks Like

• Deliver secure, reusable authentication and authorization services used by multiple product teams.
• Build high-quality .NET APIs, Angular administration tools and integration services that are maintainable and easy to operate.
• Improve the reliability, scalability and security of shared identity services through well-tested engineering changes.
• Support platform adoption by improving SDKs, documentation, developer tooling and integration patterns.
• Contribute to automation, CI/CD and cloud platform improvements that make delivery faster and more predictable.
• Collaborate with architects, product owners, QA, DevOps and consuming product teams to solve identity and access management challenges.
• Actively learn, share knowledge and contribute to a positive engineering culture.

Key Responsibilities

Identity Platform Development

• Design, develop and maintain authentication and authorization services using modern .NET technologies.
• Develop reusable platform services supporting secure authentication and authorization across multiple business applications.
• Build scalable REST APIs and integration services used throughout the organisation.
• Develop and maintain Angular-based administration portals supporting user, group and permission management.
• Contribute to the evolution of Fine-Grained Authorization (FGA) capabilities and centralized access management services.

Platform Services & Developer Experience

• Develop reusable SDKs, libraries and APIs that simplify integration with the enterprise identity platform.
• Build developer tooling that improves onboarding and adoption of shared authentication services.
• Improve developer experience by simplifying authentication, authorization and platform integration.
• Produce and maintain technical documentation supporting engineering teams consuming the platform.
• Help minimise breaking changes by designing stable, reusable platform interfaces.
• Take ownership of technical designs and implementation approaches for assigned capabilities, identifying dependencies, risks and trade-offs and following work through to a production-ready outcome.
• Lead focused technical work packages and provide practical guidance to other engineers contributing to the same capability.

Cloud & Platform Engineering

• Develop cloud-native services running on Microsoft Azure.
• Build and maintain reverse proxy capabilities using Azure API Management.
• Support Infrastructure as Code implementation using OpenTofu/Terraform.
• Contribute to CI/CD pipelines and deployment automation using Azure DevOps.
• Support continuous improvements in platform scalability, security and operational resilience.

Engineering Excellence

• Write unit, integration and automated tests ensuring platform quality and reliability.
• Participate in peer reviews, architecture discussions and technical design sessions.
• Promote engineering best practices including Clean Code, automated testing and secure software development.
• Collaborate with Product Owners, Architects, QA Engineers and Platform Engineers to deliver high-quality platform capabilities.
• Support less experienced engineers through constructive reviews, knowledge sharing and technical mentoring.

Operations & Collaboration

• Participate in third-line production support and on-call rotation.
• Investigate production issues and contribute to platform reliability improvements.
• Work closely with multiple product teams integrating with the platform.
• Share knowledge and contribute to long-term ownership of the Authentication & Authorization capability.

Qualifications

Software Engineering

• 6+ years of commercial software development experience using C# and modern .NET.
• Strong experience designing and developing REST APIs.
• Experience building scalable enterprise applications or shared platform services.
• Strong knowledge of object-oriented programming and modern software design principles.

Identity & Security

• Strong understanding of OAuth 2.0, OpenID Connect (OIDC) and JWT.
• Good understanding of modern authentication and authorization concepts.
• Experience integrating applications with enterprise identity providers.
• Understanding of secure API design and identity-based access control.

Cloud & Platform Engineering

• Experience developing cloud-native applications on Microsoft Azure.
• Experience with Azure DevOps, Git and CI/CD pipelines.
• Experience using Infrastructure as Code with Terraform or OpenTofu.
• Understanding of Azure API Management or similar API Gateway technologies.

Front-End Development

• Experience developing Angular applications using TypeScript.
• Experience building administrative or developer-facing web applications.

Engineering Practices

• Experience writing automated tests, including unit, integration and API testing.
• Experience working in Agile Scrum teams.
• Strong communication and collaboration skills.
• Ability to work effectively across multiple product teams.
• Ability to influence technical outcomes across team boundaries, communicate delivery risks and contribute to decisions affecting shared platform consumers.

Preferred Skills and Experience

• Auth0
• Fine-Grained Authorization (FGA)
• Google Zanzibar authorization model
• Azure API Management (APIM)
• SCIM integrations
• Identity Federation
• Datadog
• Playwright
• Trivy
• GitLeaks
• Invicti
• Experience building reusable developer platforms.
• Experience working with enterprise shared services.

Additional Information

The gross base salary starts from PLN 19,267 gross per month under a full-time employment contract. Remuneration is determined using objective and gender-neutral criteria, including skillset, experience and role responsibilities.

Benefits typically include private medical insurance, a dental plan and glasses reimbursement. Remuneration and benefits decisions are based on non-discriminatory, gender-neutral criteria, and current or past remuneration is not requested or considered during the recruitment process.