Senior Full‑Stack Engineer (Kotlin/React) – Remote EU

Hidden Jobs; United States; Remote; USD 140,000 - 190,000; Full time

Benefits offered by this job

Remote work within EU

Warsaw office visits

Job summary

Hidden Jobs is seeking a senior full-stack engineer to lead API and integration architecture for a team building modern web applications and backend services. The role blends hands-on coding with architectural decisions and standards.

You will design and develop REST APIs, guide architectural decisions, and lead technical discussions while collaborating across distributed teams. Willingness to visit Warsaw 1–2 times per quarter is required.

Qualifications

• Strong commercial experience with Java and Kotlin.
• Proven experience designing, building, and maintaining REST APIs.
• Hands-on API-first design with OpenAPI/Swagger.
• Solid knowledge of React and TypeScript.
• Good understanding of distributed systems and integrations.
• Practical knowledge of OAuth 2.0 and OpenID Connect.
• Experience making architectural decisions and leading technical discussions.
• English at minimum B2 and Polish at minimum B1.
• Willingness to visit Warsaw office one to two times per quarter.

Responsibilities

• Design and develop APIs that enable integrations with external business partners.
• Take a technical lead on integration architecture and contribute to key architectural decisions.
• Define API contracts following an API-first approach using OpenAPI or Swagger.
• Develop backend services with Java and Kotlin.
• Build modern web applications with React and TypeScript.
• Define and promote software development standards and best practices.
• Prepare and maintain technical documentation.
• Lead technical discussions and support the team in making sound engineering decisions.
• Work with distributed systems and complex system-to-system integrations.
• Participate in an on-call rotation.

Skills

Java

Kotlin

REST APIs

OpenAPI/Swagger

React

TypeScript

Distributed systems

OAuth 2.0/OpenID Connect

AI-assisted coding

Architectural leadership

English (B2)

Polish (B1)

Tools

Claude Code

GitHub Copilot

Cursor

Job description

Hidden Jobs is seeking a senior full-stack engineer to lead API and integration architecture for a team building modern web applications and backend services. The role blends hands-on coding with architectural decisions and standards.

You will design and develop REST APIs, guide architectural decisions, and lead technical discussions while collaborating across distributed teams. Willingness to visit Warsaw 1–2 times per quarter is required.