Kotlin / TypeScript Developer (Spring Boot + React) — Circular Economy — Paris

Abbeal is looking for a Kotlin / Java + TypeScript developer to join a product team building the core platform of a circular-economy player, on a regulated extended producer responsibility scheme. A serious technical environment: 15 Spring Boot microservices, micro-frontend applications and GCP infrastructure.

The context

The platform handles contracting, declarations, eco-contributions and pricing scales for a recycling scheme. The business domain is rich and regulated: understanding the rule before writing the code is part of the job, not an afterthought.

On the technical side the project owns its standards: hexagonal architecture and DDD across several services, several hundred Flyway migrations in production, and one rule that is not up for discussion — no change without a test.

The role

• Build and evolve Spring Boot microservices in Kotlin, with strict separation between domain, use cases, SPI ports and infrastructure adapters
• Work the PostgreSQL data model, native SQL included, and version schemas with Flyway
• Contribute to React 18/19 TypeScript frontends in an NX monorepo with module federation
• Write the tests that go with it: unit, feature and integration against a real database
• Turn regulated functional requirements into technical design, and push back when they do not hold
• Ship small, tested Merge Requests that stay within the agreed scope

What we are looking for

• Kotlin in production. A strong Java 21 developer genuinely motivated to move to Kotlin is acceptable
• Spring Boot 3.4 / Spring 6: Web, Data JPA, Security, Cloud
• JPA / Hibernate 6 and PostgreSQL, with real SQL fluency
• Microservices architecture: domain-driven split, documented REST APIs (SpringDoc/OpenAPI), asynchronous messaging
• DDD and hexagonal architecture
• Testing: JUnit 5, AssertJ, MockK. Non-negotiable on this project
• React 18/19 and TypeScript, NX monorepo and module federation
• TanStack React Query, React Final Form, react-intl, Jest and Testing Library
• Git, GitLab CI, Agile with JIRA
• Fluent French is required: part of the code, tests and documentation are written in French

Nice to have

• Docker multi-stage builds and GCP: App Engine, Cloud Run, Cloud Storage, Pub/Sub
• Asynchronous messaging such as RabbitMQ or Kafka, transferable to Pub/Sub
• Cucumber / BDD, with Gherkin scenarios written in French
• Third-party API integration: e-signature, public registries, CRM, banking flows
• Feature flags (Unleash), SonarQube, JaCoCo, Spotless / ktlint, Cypress
• Application security: JWT and fine-grained permission management

Practical details

• Paris, hybrid: 2 days a week on site (Gare de Lyon area), the rest at the team offices
• 1 to 2 remote days a week once you are fully autonomous
• 3-month assignment, renewable, starting 28 September 2026
• Freelance (around EUR 500 per day) or Abbeal permanent contract, whichever suits you
• On-site presence is required: this role cannot be done fully remote

How to apply

Send your CV to recrutement@abbeal.com. A 30-minute first call with the Abbeal team, then a technical interview on the client side.