S3-compatible object storage on Cloudflare's edge with Workers API, multipart uploads, presigned URLs, and CORS support.

• Upload, download, and manage objects via Workers bindings with HTTP metadata, custom metadata, and conditional operations; supports range requests and batch deletes up to 1,000 keys
• Multipart uploads for files >100MB (5MB–100MB parts, max 10,000 parts) and presigned URLs for direct client access (S3 domain only, requires server-side generation with expiry)
• Configure CORS in bucket settings using CLI format (rules wrapper); presigned URLs work only with {bucket}.{account}.r2.cloudflarestorage.com, not custom domains
• Use custom domains for production (never r2.dev, which is rate-limited); shard writes across keys to avoid 429 errors on concurrent writes to same object
• Prevents 13 documented issues including CORS format confusion, missing contentType, list() metadata gaps, API token permission errors, and platform outage failures; implement exponential backoff retry logic for 5xx errors