Senior API Developer – Java & Cloud Services

Ignite innovation with scalable APIs — shape the future of banking technology.Krakow-based opportunity with hybrid work model.As a Senior API Developer – Java & Cloud Services, you will be working for our client, a leading financial institution dedicated to transforming digital banking. You will design, build, and optimize secure, scalable APIs that power their cutting-edge digital products and internal platforms, leveraging modern Java and cloud-native patterns to deliver impactful solutions swiftly and reliably. This role offers an excellent platform for technical growth and innovation in a dynamic financial environment.Your main responsibilities:Build and evolve high-performing, scalable APIs and backend services using Java, Spring Boot, and Maven (developed primarily in IntelliJ).Collaborate with cross-functional teams, including engineers, product owners, architects, and testers, to deliver robust services aligned with business needs.Design APIs following industry standards (REST, GraphQL, SOAP), ensuring versioning, backward compatibility, and optimal consumer experience.Integrate with third-party and internal APIs, ensuring resilience, observability, and clear error handling.Develop and support event-driven services utilizing Kafka, managing topic design, schema evolution, and message reliability.Deploy cloud-ready services on AWS, including Kubernetes / EKS, Fargate, Redis, RDS, S3, Route 53, with consideration for deployment and runtime environments.Maintain product quality through automated testing, regular API testing, and troubleshooting live issues with a 'you build it, you run it' approach.Produce comprehensive API documentation using OpenAPI/Swagger and supporting runbooks as necessary.Contribute to engineering standards around security, performance, maintainability, and continuous improvement.You're ideal for this role if you have:At least 5 years of hands-on experience building APIs and backend services in Java.Strong expertise with Spring Boot and Maven.Solid understanding of backend architecture concepts including service design, data access, caching, and resilience.In-depth knowledge of API styles and integration patterns (REST, GraphQL, SOAP).Experience working with API tooling such as Postman, Swagger UI / OpenAPI, SoapUI.Ability to work with data formats like JSON and XML.Proven troubleshooting skills to diagnose issues, fix defects, and enhance performance and reliability.Strong collaboration skills and ability to communicate technical decisions effectively.It is a strong plus if you have:Experience with event-driven architecture at scale (Kafka streams, schema registry, idempotency, exactly-once/at-least-once).Familiarity with AWS services like Kubernetes/EKS, Fargate, Redis, RDS, S3, Route 53.Knowledge of CI/CD pipelines, observability tools (logging, metrics, tracing), and secure coding practices.Strong critical thinking and a pragmatic, delivery-focused mindset.Language Required for the role:Fluent English (spoken and written).Eligibility for the role:Only candidates with an existing legal right to work in the European Union will be considered for this role.#MAKEYourCareerBETTERInterested?

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