Senior Full-Stack Java+React Developer

Job Description This is a remote position. AIMPROSOFT is looking for a Full-Stack Java Developer (ReactJS/Spring Boot)! Aimprosoft, a fast-growing IT company, is looking for a Full-Stack Java Developer (ReactJS/Spring Boot) on a contract basis (≈ 2+ months) for an international Telecom project. This is a hands-on backend role focused on building a Service Integration Layer for a UK broadband and telecom wholesale operator. The platform will orchestrate VOIP and hardware service fulfilment between the client’s commercial order management system and downstream suppliers. You will join the project at the MVP stage and contribute to an intensive 8-week Phase 0 proof of capability. The role is a strong fit for an engineer who is comfortable working with backend integrations, long-running workflows, AWS services, and evolving technical specifications. About the project & role: The Service Integration Layer will manage complex order journeys across the client’s wholesale carrier ecosystem. Its responsibilities include service qualification, VOIP ordering, supplier orchestration, inventory updates, status tracking, and reliable recovery of interrupted processes. You will: Implement Service Qualification and Service Order APIs using Java and Spring Boot Build an adapter for integration with an external VOIP and hardware supplier Implement six supplier operations covering customer, subscription, user, and phone-number provisioning Embed and configure a workflow engine such as Camunda, Flowable, jBPM, or a similar solution Implement long-running workflows with timers, persisted state, retries, compensation, and recovery Ensure reliable asynchronous processing through idempotency, correlation IDs, timeouts, and error handling Build mocks and stubs for external systems to keep development independent of third-party sandbox availability Implement a minimum read-only Service Inventory and catalogue configuration Produce OpenAPI documentation and maintain a clear variance log for differences between the specification and implemented contracts Demonstrate durable order persistence and clean workflow recovery after an intentional mid-process restart Collaborate with the Architect, QA, DevOps, and Project Manager throughout implementation All development will take place inside the client’s AWS account, repositories, and CI/CD environment. What We Need From You: 5+ years of commercial Java development experience Strong hands-on experience with Spring Boot Commercial experience with ReactJS and the ability to develop and maintain frontend components integrated with Java/Spring Boot APIs Upper-Intermediate+ (B2+) English level Experience building REST APIs and integration-heavy backend services Solid understanding of REST and JSON API design and consumption Experience integrating with at least one non-trivial third-party API Practical knowledge of retry strategies, timeout handling, error processing, and idempotency Experience with long-running or stateful business processes using workflow engines, sagas, or state machines Understanding of asynchronous and event-driven integration patterns Experience with microservice architecture Familiarity with OAuth2-secured APIs Practical AWS experience, particularly with services such as API Gateway, ECS/Fargate, Lambda, AWS OpenSearch, RDS, SQS, or EventBridge. Basic understanding of infrastructure managed with Terraform Ability to work effectively with evolving specifications, identify ambiguities, and raise them as tracked risks Ability to deliver in a fast-paced, fixed-deadline environment Nice to have: Experience with TM Forum Open APIs Background in telecom OSS/BSS integrations Hands-on experience with Camunda 8 SaaS, Flowable, jBPM, or another BPM/workflow engine Experience embedding or operating a workflow engine as part of a Java application Understanding of process definitions, timers, compensation, and workflow state persistence Understanding of telecom order lifecycle, service qualification, inventory, or provisioning processes Experience with transactional outbox, idempotent consumers, correlation IDs, and recovery patterns Experience working with Apache Kafka or RabbitMQ Knowledge of AWS Secrets Manager Experience working on fixed-scope or fixed-deadline delivery projects Experience producing OpenAPI documentation and supporting Postman-based integration testing Bachelor’s or Master’s degree in Computer Science or a related field What We Offer: Official military deferment (reservation); A competitive salary that appreciates your skills and experience; Opportunity to join a strategically important pilot team with long-term project prospects Work on modern cloud-native products that deliver real-world impact Exposure to AI-powered development practices and enterprise-scale engineering Open environment where your ideas, technical expertise are valued