**Senior Backend Java Developer**

**Location:** European Union (remote).

**Work Arrangement:** Fully Remote.

**Contract Type:** Freelance / Contract. The rate is flexible, further details upon discussion.

**About the Role**
We are seeking an experienced **Senior Backend Java Developer** with extensive expertise in **Java** and **Spring Boot** to design and implement modern, scalable, API-first backend solutions. The successful candidate will transform functional and architectural specifications into high-quality technical designs while contributing to the evolution of a robust, cloud-native platform.
This role requires a strong technical leader capable of mentoring a small engineering squad, driving backend architecture decisions, and delivering secure, maintainable, and highly scalable services within an international Agile environment.

**Key Responsibilities**

* Design and implement scalable, API-first backend solutions using Java and Spring Boot.

* Translate functional and architectural requirements into robust technical designs.

* Lead and mentor a squad of 2--3 backend engineers, promoting engineering best practices and code quality.

* Contribute to architecture decisions, ensuring clear separation of concerns, bounded contexts, maintainability, and operational simplicity.

* Develop high-quality, well-tested code through unit, integration, and contract testing.

* Design and build RESTful APIs and event-driven services aligned with OpenAPI and AsyncAPI specifications.

* Enforce API governance standards and backend development best practices.

* Develop and maintain integrations with third-party systems using JSON, XML, and XSD.

* Design, model, and optimize MongoDB schemas while managing database migrations and transactional consistency patterns.

* Apply secure development practices, including OAuth2, OpenID Connect (OIDC), and JWT authentication mechanisms.

* Support CI/CD pipelines, trunk-based development, and cloud-native deployment practices using Docker, Kubernetes, and Helm.

* Collaborate closely with architects, business analysts, UX designers, QA engineers, DevOps, and frontend developers in an international environment.

* Participate actively in Agile/Scrum ceremonies and contribute to continuous improvement initiatives.

**Required Qualifications**

* Extensive professional experience developing backend applications with **Java** and **Spring Boot**.

* Strong experience designing scalable, API-first architectures.

* Proven ability to lead technical initiatives and mentor engineering teams.

* Solid understanding of software architecture principles, including separation of concerns and domain-driven design concepts such as bounded contexts.

* Experience developing RESTful APIs and event-driven architectures.

* Strong knowledge of OpenAPI and AsyncAPI specifications.

* Experience working with JSON, XML, and XSD, including resilient integrations with third-party systems.

* Hands-on experience modelling and optimizing MongoDB databases.

* Knowledge of database migrations and transactional consistency patterns.

* Strong understanding of application security, including OAuth2, OpenID Connect (OIDC), and JWT.

* Experience working with automated testing frameworks, including unit, integration, and contract testing.

* Experience supporting CI/CD pipelines and modern software delivery practices.

* Hands-on experience with Docker, Kubernetes, Helm, and cloud-native application deployment.

* Experience working within Agile/Scrum environments.

* Strong communication and collaboration skills within cross-functional international teams.

* English proficiency at **B2 level or higher**.

**Preferred Skills**

* Experience working in distributed, international engineering teams.

* Passion for clean architecture, software craftsmanship, and continuous improvement.

* Experience with trunk-based development methodologies.

**Location Requirements**

* Candidates must be based anywhere within **Europe**.

* Ability to work remotely while collaborating with international teams across European time zones.