Senior .NET Developer

optimum solutions (singapore) pte ltd; Singapore; On-site; SGD 60,000 - 120,000; Full time

Job summary

Optimum Solutions (Singapore) Pte Ltd is seeking a full-stack developer to design, build, and maintain microservices-based applications using .NET Core/.NET 8, Java, EF, Docker, DDD, OAuth, and AWS. The role includes REST API development, legacy migration, and security hardening.

The frontend uses ASP.NET with WebForms, HTML/CSS/JS, and a component library managed with Storybook. Collaboration with UX/UI designers is essential, along with AI-assisted coding via Spec Driven Development (SDD).

Qualifications

• Proven professional experience with .NET Core stack and modern backend technologies.
• Experience building microservices and event-driven patterns.
• Proficiency in EF for database interactions.
• Familiarity with Docker and containerization principles.
• Knowledge of DDD and security best practices.
• Experience with AWS services (S3, Lambda, API Gateway, RDS).
• Frontend proficiency in HTML/CSS/JS and ASP.NET/WebForms.

Responsibilities

• Design, develop, and maintain microservices architecture using .NET Core, .NET 8 and Java.
• Implement event-driven communication between microservices.
• Utilize EF for efficient database interactions.
• Containerize applications using Docker for scalability.
• Apply DDD principles for modular code architecture.
• Implement OAuth for authentication and authorization.
• Develop and enforce security best practices.
• Use AWS services for backend development.
• Develop RESTful APIs for frontend-backend communication.
• Apply Spec Driven Development (SDD) with Claude AI technologies.
• Support and maintain legacy .NET Framework apps and migrations.
• Manage hosting and deployment on IIS and Windows Server with config transformations.
• Frontend development with ASP.NET including WebForms; responsive UI with HTML/CSS/JS.
• Collaborate with UX/UI designers; review unit tests and maintain a design system with Storybook.
• Ensure performance optimization and troubleshooting across stack.
• Integrate OpenTelemetry for distributed tracing and observability.
• Work with Oracle databases and query optimization.

Skills

NET Core stack

C#

Java

Microservices

Entity Framework

Docker

DDD

OAuth

AWS

REST APIs

Storybook

OpenTelemetry

Oracle DB

IIS/Windows Server

OpenAI Claude/SDD

Tools

Docker

Storybook

OpenTelemetry

Job description

Key Responsibilities

Backend Development:

• Design, develop, and maintain microservices architecture using .NET Core,.NET 8 and Java.
• Implement event-driven architecture to enable seamless communicationbetween microservices.
• Utilize Entity Framework (EF) for efficient database interactions andmanagement.
• Containerize applications using Docker for scalability and deploymentflexibility.
• Apply Domain-Driven Design (DDD) principles to ensure clean and modularcode architecture.
• Implement OAuth for secure authentication and authorization.
• Develop and enforce security best practices to safeguard sensitive dataand systems.
• Utilize AWS services such as S3, Lambda, API Gateway, RDS, etc., forbackend development.
• Develop RESTful APIs endpoints to facilitate communication between thefrontend and backend.
• Apply Spec Driven Development (SDD) concepts in development of code viaClaude AI technologies.
• Support and maintain legacy .NET Framework (4.x) applications, includingmigration pathways to modern .NET where applicable.
• Manage application hosting and deployment on IIS and Windows Server environments, including environment-specific configuration management using config transformations.

Frontend Development:

• Develop responsive and user-friendly web applications using ASP.NET including WebForm applications.
• Generate and review unit tests using generative AI to ensure code quality and reliability.
• Create reusable UI components and maintain a consistent design usingStorybook.
• Collaborate closely with UX/UI designers to implement intuitive andvisually appealing interfaces.
• Troubleshoot and debug issues across the stack, ensuring smooth application operation.
• Optimize application performance and scalability for a seamless user experience.

Requirements:

• Proven professional experience working on .NET Core stack.
• Strong proficiency in .NET Core, .NET 8, C#, Java and related backendtechnologies.
• Experience building microservices architecture and implementingevent-driven design patterns.
• Proficiency in Entity Framework (EF) for database management.
• Familiarity with Docker and containerization principles.
• Knowledge of Domain-Driven Design (DDD) principles and their applicationin backend development.
• Experience implementing OAuth for authentication and authorization.
• Understanding of security best practices and their application in backenddevelopment.
• Hands-on experience with AWS services such as S3, Lambda, API Gateway,RDS, etc.
• Proficiency in frontend technologies such as HTML, CSS, and JavaScript,ASP.NET and WebForms.
• Experience writing unit tests and maintaining a design system with Storybook.
• Strong problem-solving skills and attention to detail.
• Excellent communication and collaboration skills.
• Knowledge and experience in utilizing generative AI to develop andreview codes via Spec Driven Development (SDD).
• Hands-on experience with legacy .NET Framework (4.x) applications including maintenance and incremental modernisation.
• Experience with Oracle databases, including query optimisation and integration with .NET applications.
• Proficiency in deploying and configuring applications on IIS and Windows Server, with working knowledge of Web.config transformations for environment-specific deployments.
• Hands-on experience with Java Quarkus framework, including building and deploying cloud-native microservices, with working knowledge of OpenTelemetry for distributed tracing and observability.