Senior Fullstack Engineer (Kotlin & React)

Location: Poland; work from the European Union region with a valid work permit required. Visit the client's office in Warsaw 1–2 times per quarter.

Company

hirify.global is a global AI-first digital transformation and engineering partner delivering scalable products, platforms, data-driven solutions, and AI solutions.

What you will do

• Design and develop APIs for integrations with external business partners.
• Lead integration architecture and contribute to key architectural decisions.
• Define API contracts and apply an API-first approach with OpenAPI and Swagger.
• Develop backend services with Java and Kotlin and modern web applications with React and TypeScript.
• Define software development standards, maintain technical documentation, and lead technical discussions.
• Work with distributed systems and complex integrations while participating in the on-call rotation.

Requirements

• Strong commercial experience with Java and Kotlin.
• Proven experience designing, building, and maintaining REST APIs using API-first design and OpenAPI or Swagger.
• Very good knowledge of React and TypeScript, plus a solid understanding of distributed systems and system-to-system integrations.
• Practical knowledge of OAuth 2.0 and OpenID Connect.
• Experience making architectural decisions, leading technical discussions, and defining development standards.
• English at B2 level, Polish at B1 level, work permit for the EU, and availability to work from the EU region are required.

Nice to have

• Experience with data security, GDPR, B2B integrations, and external business partners.
• Experience applying GenAI in structured software development workflows.
• Familiarity with agent-based workflows, automation patterns, and AI-augmented development.

Culture & Benefits

• Engineering-focused environment with continuous growth and knowledge sharing.
• Work on modern applications, data platforms, and AI solutions for international clients.
• Opportunity to use AI-powered assistants such as Claude Code, GitHub Copilot, and Cursor in software delivery.
• Participation in an on-call rotation.

Hiring process

• CV review.
• HR call followed by a technical interview.
• Client interview and final decision.