Large uploads should usually go directly from the client to object storage rather than passing through an application server that must relay every byte. The API authorizes an upload, creates a short-lived signed URL or multipart-upload session, and records a pending asset.

Treat client metadata as untrusted. Enforce size limits, permitted content types, ownership, quotas, and checksum validation. File extensions and browser-supplied MIME types can be forged; inspect content and scan files where the threat model requires it. Keep newly uploaded files private until validation and processing complete.

Multipart uploads improve resilience for large objects by allowing parts to retry independently. Expire abandoned upload sessions and clean up orphaned objects. Signed URLs should have narrow permissions and limited lifetimes, and logs should not expose reusable signatures.

After upload, publish an asset-processing job. Workers can inspect the file, generate thumbnails, transcode video into multiple resolutions, extract metadata, and update the asset's processing state. Queue-based processing isolates CPU-intensive tasks from interactive API traffic.

Make jobs idempotent and version outputs so a retry or new processing profile does not overwrite a newer result incorrectly. Track states such as uploaded, validating, processing, ready, rejected, and failed. Expose status to the client and distinguish retryable infrastructure failures from permanent invalid input.

Scale workers by queue age and processing cost, not only CPU. Video duration and resolution create very different workloads, so use weighted scheduling or separate queues for expensive jobs. Apply quotas to prevent a small number of users from monopolizing processing capacity.

Serve public immutable assets through a CDN with versioned paths and long cache lifetimes. Mutable resources need revalidation, shorter TTLs, or explicit purge workflows. Cache keys may include host, path, query parameters, and selected headers; unnecessary variation reduces hit ratio, while missing variation can serve the wrong representation.

Private media requires authorization-aware delivery. Signed cookies or URLs can grant temporary access, but revocation and expiration behavior must be understood. Avoid placing private user data in public cacheable URLs or logging sensitive query parameters.

Content lifecycle includes retention, legal deletion, derivative cleanup, orphan detection, and storage-tier transitions. Deleting the database record is not enough if thumbnails, transcoded variants, CDN caches, or backups remain. Define which copies are deleted immediately and which expire under a documented policy.