Do you want to join a company that places people at the heart of its concerns? We are waiting for you at Extia! Since 2007, Extia, an IT consulting firm, has been offering a unique approach in its field, combining well-being at work and performance. A successful model: more than 3000 Extians working in 20 agencies in France and abroad, 3rd Great Place To Work in France.At Extia, we follow a very simple yet effective philosophy: "First who, then what!" So let's do it together!?First, Who:You are a results-oriented professional with sharp analytical skills and a proactive mindset. You are an excellent communicator who thrives in cross-functional, agile teams.Then What:You will be responsible for the design, development, testing, and maintenance of software components critical for high-performance financial platforms.Key Responsibilities:Execute end-to-end development tasks, moving seamlessly between Java backends and modern React frontends.Implement multi-threaded applications in to ensure optimal responsiveness in low-latency environments.Apply paradigms like Domain-Driven Design (DDD), Event-Driven Architecture, and Microservices using RESTful APIs and GraphQL.Leverage AWS Services (ECS, SQS, SNS, S3, AuroraDB, Lambda) to build scalable, resilient solutions.Manage complex data layers using Oracle PL/SQL alongside NoSQL engines like DynamoDB.Work with sophisticated messaging/search engines (Kafka, Solace, Elastic Search) and serialization frameworks (Protobuf, Avro).Key Requirements:Proven experience as a Senior Backend Developer.Deep hands-on experience with JAVA.Good knowledge of Frontend technologies, specifically JavaScript and the React framework.Strong understanding of Cloud environments, specifically AWS.End-to-end experience across the full IT project lifecycle, from discovery to production operations.