Building scalable backend services and REST APIs using Node.js and NestJS. Frontend development with React Native for web and mobile applications; REST API integration; and building microsites for the custom CRM for the loyalty business partners. Database design and query optimisation with PostgreSQL / Aurora (RDS). Event-driven architecture using SQS, Kafka, and RabbitMQ. Infrastructure and deployment with API Gateway, NGINX, PM2, and performance tuning.

Migrated and redesigned a core service to Nubank's global platform, aligning with company-wide integration and modernisation standards. Worked with CRM-adjacent data systems to maintain customer-facing service continuity during migration. Backend development in Clojure; frontend components in React.

Built Node.js (TypeScript) backend modules integrated with AI-driven automation systems and external APIs. Workflow orchestration using n8n; containerized services deployed with Docker. Applied secure development practices and API validation standards using Postman and OpenAPI specs.

Led migration of a Freight Rate Calculation System from .NET to Node.js (NestJS/TypeScript): Achieved 30% faster calculations through Redis caching and algorithm optimisation. Reduced batch processing time by 40% via automated validations and refactored pipelines. Integrated SAP via RESTful API for real-time tax data; migrated storage from SQL Server to DynamoDB. Applied TDD throughout the migration lifecycle; unit test coverage with Jest.

Designed and maintained cloud-native REST APIs and serverless solutions using Azure Function Apps (including Durable Functions), Service Bus, Cosmos DB, Blob Storage, and API Management. Managed App Registrations and enforced secure development practices with Azure Key Vault for secrets management. Defined and consumed OpenAPI / Swagger specs across all API surfaces. Applied TDD with NUnit and MoQ framework; maintained high unit test coverage across all services. Implemented CI/CD pipelines in GitLab and Azure DevOps for automated build, test, and deployment. Proactively monitored performance and telemetry using Azure Application Insights in production. Integrated Kafka-based event streaming for asynchronous inter-service communication. Managed backlog and sprint ceremonies in Jira within Agile/Scrum teams.

Developed REST APIs and Web Forms apps on .NET Framework using Entity Framework and Dependency Injection patterns. Integrated with CRM data sources to generate operational reports via SSRS; optimised SQL queries on demand.

Built .NET data pipelines to move and transform data across SQL Server instances using SSIS and stored procedures. Applied secure data handling and access control practices across ETL workflows.

Developed .NET WPF desktop applications integrated with printers and POS devices; applied SOLID and OOP principles.

Developed and maintained Web Forms applications in .NET; implemented SSRS operational reports.