Senior Full-Stack Software Engineer with OAuth w Warszawa, Polska

Company Description

Technology is our how. And people are our why.

At Endava, we harness technology to drive meaningful change. By combining AI-native engineering, deep industry expertise and a people-centric mindset, we partner with leading organisations to solve complex business challenges and create digital products and platforms that make a lasting impact.

From strategy and design to engineering and operations, we help our customers accelerate innovation and transform their businesses. Join us and be part of a global team delivering work that matters.

Job Description

As part of Endava's strategic partnership with WTW, who provide data-driven, insight-led solutions in the areas of people, risk and capital, we're building dedicated software engineering teams to support WTW's Insurance Consulting and Technology Division.

WTW's Insurance Consulting and Technology business is a global leader in P&C, Life and Health insurance software and advisory services, with over 1,700 colleagues across 35 markets. More than 1,000 insurers worldwide trust our combination of advisory insight and advanced software to help them navigate complexity and drive sustainable growth.

Joining Endava, you'll work exclusively with WTW to help embed AI-enabled engineering practices, modern ways of working and deep insurance technology expertise, contributing to the next generation of products and services for insurers worldwide. Working as part of a dedicated team established through a Build-Operate-Transfer (BOT) model, you'll collaborate closely with WTW while building your career as an Endava employee, supporting the long-term success of this strategic partnership.

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. Instead, 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 ICT’s technology landscape.

You will work closely with architects, product teams, platform engineers and business stakeholders helping deliver secure, scalable and high-quality technology solutions that create value for WTW and its customers. 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

In this role you will:

• Help 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 within the Quartz team.

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 establishing long-term Endava 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 (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

For this position, the gross base salary starts from PLN 19 267 PLN Gross per month (full-time employment contract), determined using objective and gender-neutral criteria including skillset, experience and role responsibilities.

Our benefits offering typically include private medical insurance, dental plan, and glasses reimbursement. The figure represents the initial remuneration we expect to offer for this role and does not limit the right to equal pay for women and men performing the same work or work of equal value. All remuneration and benefits decisions are based on non-discriminatory, gender-neutral criteria, and in accordance with the Polish Labour Code amendments implementing Directive on pay transparency, we do not request or consider candidates’ current or past remuneration during the recruitment process.”

At Endava, we’re committed to creating an open, inclusive, and respectful environment where everyone feels safe, valued, and empowered to be their best. We welcome applications from people of all backgrounds, experiences, and perspectives—because we know that inclusive teams help us deliver smarter, more innovative solutions for our customers. Hiring decisions are based on merit, skills, qualifications, and potential. If you need adjustments or support during the recruitment process, please let us know.

At Endava, we’re committed to creating an open, inclusive, and respectful environment where everyone feels safe, valued, and empowered to be their best. We welcome applications from people of all backgrounds, experiences, and perspectives—because we know that inclusive teams help us deliver smarter, more innovative solutions for our customers. Hiring decisions are based on merit, skills, qualifications, and potential. If you need adjustments or support during the recruitment process, please let us know.