Senior Fullstack Engineer (Java & Kotlin + JavaScript)

About the role

We are looking for a Senior Fullstack Engineer to lead API design and partner integration for one of Europe’s largest e‑commerce platforms. You will act as the technical anchor, bridging Java/Kotlin backend services with modern JavaScript front‑end solutions.

Key responsibilities

• Design robust API contracts, write developer documentation, and create mock environments for external partners.
• Develop modern web interfaces (checkout flows, landing pages, discovery hubs) using React.
• Provide technical leadership, define coding standards, and ensure cohesive end‑to‑end implementation.
• Collaborate with backend teams to align Java/Kotlin services with front‑end requirements.
• Participate in incident response and support production stability.

Required profile

• Deep, hands‑on experience with Java and Kotlin.
• Proven track record designing, building, and scaling RESTful APIs (API‑first, OpenAPI/Swagger).
• Strong front‑end expertise in modern JavaScript/TypeScript, preferably React.
• Solid understanding of distributed systems, integration patterns, and secure authentication (OAuth 2.0, OpenID Connect).
• Ability to define coding standards, lead technical discussions, and design flexible B2B API contracts.
• English level B2+ and availability for incident response.

Required skills

• Java
• Kotlin
• RESTful APIs
• OpenAPI / Swagger
• JavaScript
• TypeScript
• React
• OAuth 2.0
• OpenID Connect
• Distributed systems
• Integration patterns

What we offer

• Collaborative, growth‑focused environment.
• Opportunity to work on high‑traffic e‑commerce services.
• Exposure to cutting‑edge technologies and large‑scale integrations.