Design large video upload for a YouTube-like app

## System Design Prompt Design the **video upload subsystem** for a YouTube-like product that supports **large video files**. ### Core user flow 1. User selects a large video file (hundreds of MB to tens of GB). 2. Upload should be **reliable** (resume after network drops). 3. After upload, the platform processes the video (e.g., transcode) and eventually makes it playable. ### Requirements - Support **resumable uploads** and unstable mobile networks. - Efficiently handle large files (chunking, retries, integrity checks). - Provide upload status to clients (progress, failure reasons). - Ensure uploaded content is durable and not lost. - Basic security: authenticate users, authorize uploads, prevent misuse. ### Scale assumptions (state your own if needed) - Millions of users - Spiky traffic (new releases) - Global uploads ### Deliverables - APIs, data model, and high-level architecture - Storage strategy for raw uploads and processed outputs - Processing pipeline (transcoding, thumbnails) - Failure handling, idempotency, and observability - Key trade-offs