
How to Upload Large Files in ASP.NET Core Using S3 Multipart Upload and Presigned URLs
Learn how to efficiently upload large files in ASP.NET Core using Amazon S3's multipart upload feature and pre-signed URLs. This hands-on guide walks you through building a scalable, client-driven upload workflow using a .NET 9 Web API and a Blazor WebAssembly frontend. You'll learn how to generate pre-signed URLs, handle file chunking, perform parallel uploads, and finalize the upload with minimal server load. Ideal for developers looking to offload file handling to S3 while maintaining full control from a .NET-based stack.