file-storage-standard

S3 presigned URLs enable direct browser uploads by embedding Content-Type and file size constraints into the signed request. The server generates these URLs to enforce MIME type validation and strict size limits before the upload reaches the S3 bucket.

Multi-tenant S3 storage isolation is achieved using tenant-scoped key prefixes for every uploaded file. This pattern ensures each tenant's files are logically separated within the bucket, while server-side metadata enforces access control per file.

CloudFront CDN delivery uses per-file metadata to determine access control before serving cached files. The distribution integrates with S3 bucket policies to ensure only authorized users can download files through the CDN edge locations.

Multipart upload workflows are fully supported for large files alongside presigned URLs. The server-side logic manages the multipart lifecycle, allowing robust chunked uploads to S3 while maintaining metadata and access control.

CloudFront is not strictly required for S3 delivery but is configured for fast, cached file access. Using the CDN reduces direct S3 fetch latency and provides edge delivery while maintaining per-file access control.

S3 bucket policies for tenant isolation must restrict access based on tenant-scoped key prefixes and per-file metadata. The configuration enforces server-side validation, lifecycle rules, and secure delivery through CloudFront distributions.