Muhammad I.

Senior .NET developer and solution architect. I build RESTful ASP.NET Core Web APIs, multi-tenant SaaS and Azure backends in C#, migrate legacy .NET to .NET 8/10, and add AI where it earns its place. Top Rated, 100% Job Success, 2,170+ hours on Upwork. Most of my work starts with a .NET system that already exists and has to keep working: a slow API, a monolith that needs to become services, a .NET Framework app stuck on an old server, a SaaS product that has to hold more tenants without falling over. WHAT I BUILD - APIs and backends: ASP.NET Core Web APIs, versioning and OpenAPI docs, authentication and rate limiting, Entity Framework Core with SQL Server or Cosmos DB, background jobs and messaging, structured logging and health checks. - Azure: App Service, Azure Functions and isolated workers, Service Bus, Event Grid, Docker, Container Apps and AKS, with CI/CD on Azure DevOps or GitHub Actions. - Multi-tenant SaaS and architecture: tenant isolation, role-based access, microservices where they help, Domain-Driven Design and CQRS, and written architecture and security documentation your team can keep. - Modernization: .NET Framework, WebForms, MVC and WCF applications moved to modern .NET with a phased plan, tests and a rollback path. I migrated a legal SaaS platform and a fintech payment API to .NET Core with zero downtime. - AI inside .NET products: Azure OpenAI, retrieval-augmented generation with citations, Azure AI Search and tool-calling agents for AI automation, wired into your existing C# code and permission model. - Secure sign-in: Microsoft Entra ID, OAuth 2.0 and OpenID Connect, single sign-on, app roles and Microsoft Graph access scoped to the signed-in user. WHERE I HAVE DONE IT Top Rated with 100% Job Success across 2,170+ hours on Upwork, including a 1,800+ hour lead developer engagement on a .NET and AI product and a 300+ hour Azure DevOps CI/CD contract. Elsewhere: AI document review on Azure OpenAI, a Power BI Embedded insurance dashboard, a microservices security platform on Docker and Kubernetes, and multi-tenant SaaS on Azure for legal, insurance and fintech teams. Open-source contributor to the .NET ecosystem, with merged pull requests in FastEndpoints and Mapperly and corrections to Microsoft's .NET, EF Core and Dynamics 365 documentation. HOW I WORK I start with the data model, the permission model and the deployment path, then write C# the next developer can read. You get a short architecture note before the code, weekly updates, tests around the risky parts, and a handover document at the end. Tell me what your system does today and what it has to do next, and I will tell you what it actually takes.