Mid/Senior Java Developer (Backend)
- Compensation
- Not disclosed
- Location
- Not listed
- Work setup
- Not specified
- Seniority
- Senior
- Employment
- Contract
- Experience
- Not specified
- Category
- Backend
- Posted
Skills
Must have
- At least five years of commercial Java development experience
- Very good knowledge of Java and Spring Boot 3
- Hands-on knowledge of Spring Security and Spring Data JPA
- Experience with BPMN workflow engines such as Flowable or Camunda
- Experience embedding a workflow engine within an application or a good understanding of the embedded deployment model and shared transactions
- Very good knowledge of PostgreSQL, including query optimisation, indexing strategies and connection pool management
- Experience designing and developing REST APIs
- Practical knowledge of OpenAPI or Swagger and the specification-first approach
- Experience creating integration tests with Testcontainers
- Knowledge of architectural patterns used in multi-tenant SaaS platforms
- Understanding of tenant context propagation, data isolation and query-scoping mechanisms
- Experience working with pull requests, code reviews and CI-based development processes
- Very good written and spoken English and Polish
- Independence, ownership of implemented solutions and readiness to work in close partnership with the Lead Software Architect
Full description
Contract type: B2B
Rate: PLN 120–165 net/hour
Commitment: Full-time
Work model: Remote or from the VM.PL office in Wrocław
Project start: October 2026
Duration: till the end of January 2027
About the project
You will join a project delivered for a client from the DACH region that is developing a compliance services platform for telecommunications companies.
We are building a multi-tenant, cloud-native SaaS platform from the ground up. It will support the handling of data production and preservation orders in accordance with the EU e-Evidence Regulation. The system will process sensitive data related to criminal proceedings, which means it must meet strict requirements concerning security, data isolation, document immutability and data residency within the European Union.
Your main responsibility will be to implement the key backend components: a Flowable BPMN engine embedded as a library within Spring Boot, a multi-tenant data access layer and a REST API integrating the platform with telecommunications operators’ systems.
The backend will handle EPOC and EPOC-PR orders, including cases with a legally binding processing deadline of only eight hours. This is not a standard CRUD application. We are looking for people who can design and develop complex business processes, tenant isolation mechanisms and solutions requiring high levels of consistency and reliability.
Technologies
Java 21, Spring Boot 3, Spring Security, Spring Data JPA, Flowable 6, BPMN, PostgreSQL, Row-Level Security, REST, OpenAPI 3, Keycloak, OIDC, JWT, S3 Object Lock, JUnit 5, Testcontainers, ArchUnit, GitLab CI, GitHub Actions, Semgrep, CodeQL, Snyk, Trivy, Claude Code, GitHub Copilot, CodeRabbit
Responsibilities
- Implementing BPMN processes in Flowable for the complete EPOC and EPOC-PR case lifecycle
- Configuring the Flowable engine as a library embedded within the Spring Boot application, using shared database transactions
- Building a multi-tenant data access layer and enforcing tenant isolation at the repository and PostgreSQL Row-Level Security levels
- Creating ArchUnit tests to verify that the code does not allow access to data belonging to other tenants
- Developing REST APIs for case creation, status queries and document uploads
- Designing API contracts using an OpenAPI specification-first approach
- Integrating the platform with external telecommunications operators’ CRM systems using the adapter pattern