**Description and Responsibilities:** **Schedule:** TO BE AGREED **Level:** Professional **Employment Type:** Permanent – CLT Implement REST APIs in .NET 9 / ASP.NET Core, with versioning, content negotiation, and standardized error responses (202/409/422); Build robust validations, including JSON Schema/OpenAPI, data sanitization, and authentication/authorization (OAuth2/JWT), verifying HMAC where applicable; Apply reliability patterns: idempotency via header, deduplication, retry/backoff, circuit breaker, timeouts; Model and optimize data using EF Core (migrations) and SQL Server / Azure SQL (indexes, execution plans, locking/isolation, transactions); configure retention/purge; Deliver files via Download API (stream from private Blob with SAS/OAuth2/ETag); Integrate with Azure Service Bus (prefetch, lock renewal, DLQ, reprocessing) and maintain a unified DeliveryLog; Develop essential operational UIs in React/TypeScript or Blazor: dense/virtualized grids, timelines, log/document viewers, and front-end RBAC; Instrument observability: structured logging, traceId/spanId correlation, p95/p99 metrics, and dashboards in App Insights/Log Analytics. **Requirements:** Experience in C# / .NET Core 9 and ASP.NET Core Web API; EF Core and advanced SQL (indexes, execution plans, transactions, locks); Implementation of resilience patterns (retry/backoff, circuit breaker) and best practices for HTTP integration; Experience with Azure: App Service/Container Apps, APIM (basic policies), Service Bus (DLQ), Azure SQL, Blob Storage, Key Vault, and Managed Identity; API contracts: OpenAPI/Swagger, JSON Schema; contract testing with Postman/Newman or similar tools; Security: OAuth2/JWT, HMAC, TLS/CORS; basic understanding of LGPD (logs without sensitive PII); UI: React/TypeScript (or Blazor) for operational screens; basic accessibility knowledge; Observability: App Insights, OpenTelemetry (basic), KQL (basic). Languages: Technical English for reading and writing (desirable). **Benefits:** Health insurance, Dental insurance, Childcare allowance, Food voucher, Meal voucher