Mahammad M.

Senior Full-Stack .NET Engineer with 5+ years building scalable SaaS platforms, billing systems, and high-performance REST APIs using ASP.NET Core, ABP Framework, C#, Angular, and React. I specialize in subscription billing with Stripe, AI/LLM integration, microservices, and production-grade systems built for scale and long-term maintainability. I deliver reliable backend systems, multi-tenant SaaS platforms, API-driven applications, and full-stack solutions that are secure, performant, and built to last. — WHAT I DELIVER — Scalable ASP.NET Core / ABP Framework backends for SaaS End-to-end Stripe billing (subscriptions, metered usage, credit grants, prorated upgrades, idempotent webhooks) AI-powered platforms (Claude, OpenAI, Semantic Kernel) REST APIs and microservices Full-stack SaaS development Real-time systems (SignalR) Self-hosted SaaS infrastructure on Hetzner + Coolify (cost-effective AWS alternative) Cloud-ready containerized deployments — BACKEND — ASP.NET Core / .NET 6–10 | ABP Framework (Volo) — modules, multi-tenancy, permissions, background workers, distributed events | C# | DDD | CQRS | Clean Architecture | SOLID | EF Core | PostgreSQL | SQL Server | Redis | OpenIddict | JWT | OAuth2 | RabbitMQ — PAYMENTS — Stripe Billing (V1+V2) | Subscriptions & metered billing | Credit grants & expiry | Proration logic | Webhook idempotency + concurrency-safe handlers | Stripe Tax | SCA / 3DS — AI / LLM — Anthropic Claude | OpenAI GPT | Semantic Kernel | Prompt engineering | Token-cost tracking | Multi-provider routing | Image generation — FRONTEND — Angular (signals, standalone components, OnPush, @if/@for/@let) | React | TypeScript | RxJS | Reactive forms | Bootstrap 5 | LeptonX — CLOUD & DEVOPS — Docker | Kubernetes | Hetzner | Coolify | AWS (EC2, RDS, S3) | Vercel | Cloudflare R2 | GitHub Actions / Workflows | CI/CD pipelines | Self-hosted PaaS deployments — ALSO — WPF (MVVM) | xUnit | Serilog | Performance profiling | Agile / Git workflows — IF YOU'RE LOOKING FOR — ABP Framework specialist Stripe Billing engineer (subscriptions, metered, idempotency) AI SaaS backend developer Self-hosted infrastructure setup (Hetzner + Coolify) Full-stack SaaS / microservices / scalable REST APIs Senior-level .NET engineer for scalable, production-ready SaaS, especially platforms with subscription billing or AI integration. Let's talk.