Senior Fullstack Engineer (Java+React)

Project overview

Who is H2B Group?

We are a consulting company that helps clients automate business processes using AI, and IT specialists develop their careers in a B2B model. We offer projects in industries such as fintech, medtech, edutech, and industrial automation. Through close cooperation, we support our clients' development by delivering fast and measurable results, while providing IT specialists with career development opportunities and valuable experience.

Why cooperate with us?

For our client's project, we are looking for

We are looking for candidates for the positions of Full-Stack Developer and Full-Stack Tech Lead (Java + React) for the engineering team developing an advanced pricing platform. The team will eventually consist of 1 Tech Lead and 5 Developers working in an innovative agent-first delivery model.

The client is developing a scalable pricing platform, including national price list management, discounts, margins, and multi-stage validation workflows. The key challenge in the project is to ensure the precision of mathematical and financial calculations over time (temporal data, validity periods) and full auditability under the separation of duties regime (compliance / separation of duties). Work is carried out in an agent-first approach, where AI agents perform programming tasks under the technical supervision of engineers.

Scope of duties for this position

Developer Role:

Tech Lead Role (additional):

• Flexibility – You choose projects tailored to your skills and interests, with the option to change within our company or the Euvic group, of which we are a part.
• Transparency – You have clear cooperation rules and full transparency of remuneration and conditions.
• Speed of action – Thanks to our efficiency, you will quickly find or change a project that perfectly matches your competencies.
• Development opportunities – You work on innovative projects, developing key competencies and gaining valuable experience.
• Development and optimization of typed user interfaces (React 18 / TypeScript, data grid components) and backend services in the Java ecosystem (Spring Boot).
• Implementation and maintenance of business rules, pricing calculation engine, and temporal data models in a PostgreSQL database.
• Daily work in the agent-first model: decomposition of business requirements into precisely defined tasks for AI agents, providing necessary context.
• Configuration and maintenance of instructions for AI agents, context files, and repository domain dictionaries.
• Conducting critical, skeptical code reviews of AI-generated code for security vulnerabilities, code redundancy, and logical correctness.
• Creating unit, integration, and E2E tests and ensuring automatic quality gates.
• Hands-on technical leadership of the team, close cooperation with the Product Owner regarding architecture and scope of work, and optimization of the AI agent-based workflow.
• Creation and documentation of architectural decisions (ADRs) and operational procedures (runbooks).
• Establishing rules for task division between automatic AI tools and engineering programming and verification work.
• Design and maintenance of rigorous quality gates (ArchUnit, Spring Modulith, mutation testing, Testcontainers).
• Design of calculation algorithms, database structures in PostgreSQL, and security and permissions architecture (RBAC).
• Supervision of CI/CD processes, container deployments on Kubernetes, and proactive analysis and elimination of vulnerabilities.
• Mentoring team members and establishing common technical standards.

Requirements

Additionally for the Tech Lead role:

• Minimum 5 years of commercial experience in full-stack software development using Java (Spring Boot) and React (React 18 / TypeScript).
• Very good knowledge of SQL databases, especially PostgreSQL (query and index optimization).
• Practical experience in daily work with AI tools / coding agents (task decomposition, context definition, prompt engineering).
• Experience and discipline in skeptical code review of code generated by LLM models / AI agents (detecting fake tests, vulnerabilities, and over-engineering).
• Proficiency in writing unit, integration, or E2E tests.
• Ability to precisely model complex domain issues: financial calculations, rounding, time-dependent data (validity periods), and audit trails.
• Fluent knowledge of English, spoken and written (minimum B2/C1).
• Experience as an architect or technical lead of an engineering team.
• Practice in implementing and scaling AI agent-based development processes.
• Advanced knowledge of designing code quality control mechanisms (ArchUnit, Spring Modulith, mutation tests, Testcontainers).
• Deep knowledge of secure software design and role-based access control (RBAC).

Nice to have

What we offer?

Remote work – flexibility that allows you to work from anywhere in the world!

Interesting projects – selected according to your skills and interests, offering the opportunity to work on innovative solutions.

B2B contract without an exclusivity clause – cooperate with us on your terms.

Professional development – working with the latest technologies and in diverse projects guarantees continuous development.

• Knowledge of German.
• Experience in the financial, e-commerce, or pricing calculation systems industry.
• Practical knowledge of tools: MUI (MUI X DataGrid), Spring Modulith, Flyway, Testcontainers, Playwright / Gherkin.
• Infrastructure experience: Azure DevOps (Pipelines, Agents), Kubernetes / Helm.
• Knowledge of integration with SAP systems or Solace broker (event-driven architecture).
• Knowledge of engineering metrics (e.g., DORA) and methods for measuring work efficiency with AI agents.

Project details

• Start: flexible
• Remote: remote
• Location: Gdańsk, Abrahama 1a, PL
• Rate: 120-160 EUR/h
• Languages: Polish