Software Engineer – Callista / Oracle & Azure (API & Event-Driven)
We're looking for a Software Engineer with strong Callista experience to support the design and delivery of event-driven and API-based services. This role sits at the intersection of Oracle ORDS, Callista, and Azure serverless technologies, helping modernise and extend legacy platforms through cloud-native integrations.
The successful candidate will be responsible for building and extending Callista-based services, integrating Oracle ORDS APIs with an Azure pub/sub messaging backbone using Azure Function Apps.
Key Responsibilities
* Design, build, and support Callista-based services and integrations
* Develop and expose APIs using Oracle ORDS, PL/SQL, and advanced SQL
* Build event-driven and API-driven services using Azure Functions
* Integrate legacy systems with Azure Service Bus / Event Grid / Event Hubs
* Design resilient integrations with retry logic, idempotency, and structured error handling
* Collaborate on data modelling, entity relationships, and API contracts
* Implement secure cloud solutions using Azure best practices
Required Technical Skills Callista (Core Requirement)
* Strong hands-on experience with Callista
* Experience building, extending, or supporting Callista-based services
* Ability to integrate Callista with Oracle ORDS APIs and cloud platforms
Oracle & Database
* Strong hands-on experience with Oracle ORDS for API development
* Advanced PL/SQL and SQL
* Experience with Oracle JSON functions
* Ability to analyse and model database entities and relationships
* Solid understanding of RESTful API design principles
Azure & Cloud
* Strong hands-on experience with Azure Functions (serverless)
* Experience with Azure Service Bus (or Event Grid / Event Hubs)
* Strong understanding of pub/sub integration patterns
* Experience designing and implementing event-driven and API-based microservices
Security & Best Practices
* Experience implementing secure solutions using:
* Managed Identity
* Azure Key Vault
* Best-practice API security patterns
Nice to Have
* Azure and/or Oracle cloud or database certifications
* Experience modernising or integrating legacy enterprise platforms
* Background in integration-heavy or event-driven architectures