Senior Backend Developer (Java / Spring Boot)

About the Project
You'll join our client's team working on a live, production B2B SaaS platform in the sales/revenue operations space including pipeline management, sales process configuration, risk alerting, and role-based analytics.
The client's product is fully launched and actively used in production. It runs on AWS, uses enterprise SSO (OAuth2/OIDC), and integrates with an external data platform.
This is not a greenfield project you'll be working with an established codebase and existing engineering practices, including automated testing, pre-commit hooks, and CI enforcement. Your focus will be on extending backend functionality, improving architecture, and further strengthening the platform.

Responsibilities
Build, maintain, and extend backend functionality using Java and Spring Boot
Design and develop REST APIs and backend integrations
Work within and help enforce a hexagonal / DDD-oriented architecture, keeping domain logic decoupled from framework and persistence concerns
Raise automated test coverage across domain and application layers and maintain a strong testing culture
Help introduce architecture-conformance checks, such as ArchUnit, to enforce dependency boundaries
Contribute to migrating backend dependencies from early-access or milestone releases to stable GA versions as part of ongoing platform hardening
Maintain and extend OAuth2/OIDC-based authentication and role-based access control
Work with PostgreSQL, database schema evolution, and Flyway migrations
Maintain integrations with external data platforms, including Databricks
Strengthen secrets and credentials management across the codebase and CI/CD
Participate in code reviews, technical design discussions, troubleshooting, and production incident response

Requirements
5+ years of professional backend development experience
Strong production experience with Java and Spring Boot
Strong understanding of REST API design and backend architecture
Hands-on experience with Spring Security and OAuth2/OIDC flows
Strong PostgreSQL experience and knowledge of schema migration tooling such as Flyway
Experience with AWS
Strong testing discipline with JUnit 5 and Testcontainers
Experience with Docker and container-based deployment, ideally AWS ECS/Fargate or equivalent
Comfortable working with or refactoring toward hexagonal, clean, or DDD-oriented architecture
Understanding of CI/CD and production engineering practices
English Upper-Intermediate or higher

Nice to Have
Experience with AWS Secrets Manager and cloud secrets management
Experience integrating with data platforms such as Databricks
Experience with ArchUnit or similar architecture-enforcement tooling
Experience modernizing or hardening mature production codebases
Experience migrating framework or library dependencies from early-access versions to stable GA releases
Experience with monitoring and observability tools such as Datadog