Middle Fullstack Engineer (Kotlin&React)

Xebia; Poland; On-site; PLN 180,000 - 240,000; Full time

Job summary

Xebia is seeking a software professional to develop and enhance microservices using Java and Kotlin, and to design REST APIs and frontend components with React. You will work across backend and frontend areas, collaborating with partners and the team to deliver features efficiently.

The role requires 3+ years of experience, strong REST/JSON skills, and openness to occasional Warsaw office visits. Work from the EU region with a valid work permit is required.

Qualifications

• 3+ years of commercial software development experience.
• Good knowledge of Java and Kotlin.
• Practical experience with microservice architectures.
• Good knowledge of HTML and CSS.
• Strong understanding of REST API design and consumption.
• Practical experience with JSON.
• Willingness to work across backend and frontend development.
• Experience using AI-powered assistants to improve productivity in software delivery.
• Ability to quickly switch between different technologies and tasks.
• Good communication and collaboration skills.
• English at least B2 level.
• Polish at least B1 level.
• Openness to occasional visits to the Warsaw office (1-2 days per quarter).
• Work from the European Union region and a work permit are required.

Responsibilities

• Developing and enhancing microservices using Java and Kotlin.
• Designing, developing, and modifying REST APIs and backend mocks.
• Building web components, purchase flows, and registration processes using React.
• Working across both backend and frontend areas, adapting to changing project needs.
• Integrating solutions with external business partners and supporting partner-facing functionalities.
• Collaborating with the team to deliver new features quickly and efficiently.
• Contributing to the continuous improvement of the product and technical solutions.

Skills

Java

Kotlin

Microservices

REST API

HTML/CSS

JSON

React

English (B2)

Polish (B1)

AI-powered tools (e.g., Claude Code, C

Tools

Docker

GitLab CI

CI/CD

Job description

Xebia is a global AI-first, digital transformation, and engineering partner. With over 25 years of experience and a team of 5,000 professionals across 16 countries, we help organizations design and build scalable products, platforms, and data-driven solutions.

We specialize in Artificial Intelligence, Data and Cloud, Intelligent Automation, and Digital Products, combining deep technical expertise with a strong focus on engineering excellence and a people-first culture.

In the CEE region, we’re a team of nearly 1,000 experts delivering modern applications, data platforms, and AI solutions for clients such as McLaren, Aviva, Deloitte, Spotify, Disney, ING, UPS, Tesco, Truecaller, AllSaints, Volotea, Schmitz Cargobull, Allegro, InPost, and many, many more. We work with leading technologies including AWS, Azure, GCP, Databricks, and Snowflake, and combine strong engineering culture with a consulting mindset and a continuous focus on growth and knowledge sharing.

You will be:

• developing and enhancing microservices using Java and Kotlin,
• designing, developing, and modifying REST APIs and backend mocks,
• building web components, purchase flows, and registration processes using React,
• working across both backend and frontend areas, adapting to changing project needs,
• integrating solutions with external business partners and supporting partner-facing functionalities,
• collaborating with the team to deliver new features quickly and efficiently,
• contributing to the continuous improvement of the product and technical solutions.

Your profile:

• 3+ years of commercial experience in software development,
• good knowledge of Java and Kotlin,
• practical experience working with microservice architecture,
• good knowledge of HTML and CSS,
• solid understanding of REST API design and consumption,
• practical experience working with JSON,
• willingness to work across both backend and frontend development,
• practical experience using AI-powered assistants (e.g. Claude Code, GitHub Copilot, Cursor) to improve productivity, quality, or decision-making in software delivery,
• ability to quickly switch between different technological areas and tasks,
• good communication and collaboration skills,
• English at min. B2 level,
• Polish at min. B1 level,
• openness to occasional visits to the Warsaw office (1-2 days per quarter).
• Work from the European Union region and a work permit are required.

Nice to have:

• experience with Docker and CI/CD processes, particularly GitLab CI,
• experience working with cloud environments,
• understanding of UX/UI principles,
• familiarity with Responsive Web Design (RWD),
• experience integrating with external partner systems,
• experience applying GenAI in a more structured way within the SDLC, including defined workflows, prompt patterns, or tool integrations embedded into daily work,
• interest in and familiarity with emerging AI-driven practices (e.g. agent-based workflows, automation patterns, AI-augmented development), with a willingness to explore and experiment beyond standard approaches.

Recruitment Process:

CV review – HR call – Technical Interview – Client Interview – Decision