How would you implement a file upload feature from a React or Next.js UI to an ASP.NET Core backend?

In production I would add malware scanning, content-type verification, quotas, retention, cleanup for abandoned uploads, and telemetry for upload failures and storage latency. I would avoid trusting client filenames or extensions, and I would keep server-generated storage keys. Large uploads need backpressure and memory-safe streaming. If files are sensitive, audit downloads, encrypt storage, and avoid showing private content in logs, previews, or error messages. I would also test upload interruption, rejected file type, oversized file, expired session, and scan failure so the user always gets a recoverable state.