Mid/Senior Full-Stack Engineer (Java/Kotlin & JavaScript)

Quick Facts

• Role: Mid/Senior Full-Stack Engineer (Java/Kotlin & JavaScript)

• Domain: New ventures and partner integrations for an e-commerce platform

• Focus: API design/integration, modern frontend development, technical leadership

Description

You will help launch innovative services with external strategic partners, where partners integrate by calling the platform’s APIs. As a technical leader and architectural anchor, you will design robust API contracts, build mock environments and developer documentation, and develop modern web interfaces that consume partner services. You’ll bridge Java backend architecture with modern frontend implementation to deliver cohesive end-to-end functionality.

Responsibilities

• API Design & Partner Integration: onboard external partners by creating API contracts, high-quality developer documentation, and mock environments

• Frontend Development: build modern web interfaces (checkout flows, landing pages, discovery hubs) consuming integrated partner services

• Technical Leadership: connect Java backend design with modern frontend development for end-to-end implementation

Requirements

• Deep, hands-on experience in Java and Kotlin

• Strong experience designing, building, and scaling RESTful APIs (API-first design, OpenAPI/Swagger)

• Excellent frontend skills with modern JavaScript/TypeScript and a modern framework (React preferred)

• Solid knowledge of distributed systems, integration patterns, and secure authentication (OAuth 2.0, OpenID Connect)

• Ability to define coding standards, lead technical discussions, and design flexible API contracts for external B2B partners

• English level minimum B2+

• Availability for the Incident Response service

Benefits

• B2B contract: 20–26k PLN

• Access to the Worksmile platform

• Growth- and innovation-oriented work environment with room for your ideas