Java fullstack engineer

Vacant; Enschede; On-site; EUR 70,000 - 110,000; Full time

Job summary

Vacant is seeking a proactive software engineer to join our Identity & Access Management team. You will work on high-throughput authentication and authorization services using Java, Keycloak, Go, and Kotlin, and build frontend dashboards in React to support identity journeys.

You'll support polyglot ecosystems with .NET SDKs and Python automation, deploy microservices with Docker, Kubernetes, and AWS, and help raise security and observability standards across the platform.

Qualifications

• Commercial backend engineering experience with Java as a focus.
• Hands-on experience with identity protocols (OAuth 2.0, OpenID Connect, SAML).
• Frontend experience with React (JavaScript/TypeScript) is a plus.
• Experience operating production services with Kubernetes, Docker, and AWS.
• Familiarity with .NET client SDKs and Python automation scripting.

Responsibilities

• Build, scale, and maintain identity services and authorization microservices.
• Deliver end-to-end features with React admin dashboards.
• Support polyglot ecosystems and client SDKs.
• Drive cloud infrastructure and reliability with Docker, Kubernetes, and AWS.
• Elevate security patterns, observability, and architectural reviews.

Skills

Java

Go

Kotlin

React

OAuth 2.0

OpenID Connect

SAML

RBAC/ABAC

Kubernetes

Docker

AWS

Python

.NET

Tools

Keycloak

SDKs

Python

Docker

Kubernetes

AWS

Job description

Hungry for a challenge? Our mission? To empower every food moment around the world, whether it is through customer service, coding, or couriers.

The Opportunity:

We are looking for a proactive software engineer with a strong backend foundation and full-stack capabilities to join our Identity & Access Management (AuthN/AuthZ) team. As a Full-Stack Engineer, you will bring solid experience in security architectures, identity systems, and distributed microservices to the table. In this role, you will be instrumental in building high-throughput authorization services, extending enterprise authentication workflows, maintaining developer SDKs, and delivering intuitive frontend interfaces for our global ecosystem.

In this role you'll have the responsibility to:

• Build & Scale Identity Services: Design, develop, and maintain enterprise Authentication infrastructure built primarily on Java and Keycloak, alongside high-concurrency Authorization microservices in Go and Kotlin.
• Deliver End-to-End Features (React): Build clean, secure, and responsive frontend applications and admin dashboards using React to support seamlessly integrated user and partner identity journeys.
• Support Polyglot Ecosystems & Tooling: Support client-side .NET SDKs and write Python automation scripts to streamline developer onboarding, authorization checks, and ops automation across JET teams.
• Drive Cloud Infrastructure & Reliability: Package, deploy, and scale microservices using Docker, Kubernetes (k8s), and AWS, ensuring high availability, fault tolerance, and tight security controls.
• Elevate Technical Standards: Implement modern security patterns (OAuth2, OIDC, RBAC/ABAC), adhere to observability standards, and actively participate in collaborative architectural reviews and team knowledge sharing.

What Will You Bring to the Table?

• Solid Java Backend Experience: Commercial experience in backend engineering, with a strong primary focus on Java, and comfort working in a polyglot environment (Go, Kotlin).
• Domain Knowledge in AuthN & AuthZ: Hands-on experience with identity protocols (OAuth 2.0, OpenID Connect, SAML) and custom/open-source identity providers such as Keycloak.
• Frontend Capabilities: Nice to have hands-on proficiency or willing to work with React (JavaScript/TypeScript) to deliver modern, end-to-end full-stack solutions.
• Cloud & Container Experience: Experience operating services in production with Kubernetes (k8s), Docker, and AWS cloud services.
• SDK & Scripting Versatility: Familiarity or comfort working with .NET (for internal client SDK maintenance) and Python (for automation and tooling).
• AI-Assisted Development & SRE Mindset: Comfortable leveraging AI coding assistants to accelerate development, paired with an operational mindset focused on monitoring and reliability.

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