Is it safe to generate R2 presigned URLs on the client side?

No. You must always generate presigned URLs on the server-side (using a Worker or backend) to avoid exposing your R2 access keys and secret keys.

What are the advantages of using R2 over S3?

Cloudflare R2 offers zero egress fees, deep integration with Cloudflare Workers, and full S3 API compatibility, making it significantly more cost-effective for high-bandwidth applications.

How do I fix CORS errors when uploading from a web browser?

CORS must be configured in the R2 Bucket settings in the Cloudflare Dashboard. You need to define allowed origins, methods, and headers to permit browser-based PUT or GET requests.

How do I handle files larger than 100MB in R2?

For files exceeding 100MB, use the multipart upload API. This skill provides patterns to initialize, upload parts (5MB-100MB each), and complete the transfer reliably.

Does this skill support the 2025 R2 updates?

Yes, it includes guidance on the latest features such as R2 SQL for Apache Iceberg, Pipelines for stream ingestion, and increased bucket limits.

Cloudflare R2 Object Storage

Name: Cloudflare R2 Object Storage
Author: jezweb

byjezweb

•

Cloud Infrastructure

Integrates Cloudflare R2 into Claude Code for managing S3-compatible object storage, presigned URLs, and multipart uploads.

This skill empowers Claude Code to interact efficiently with Cloudflare R2, providing specialized guidance for the Workers API, large-scale multipart uploads, and secure presigned URL generation. It includes production-ready implementation patterns for managing metadata, configuring CORS policies, and troubleshooting common storage errors. By leveraging this skill, developers can implement cost-effective, zero-egress storage solutions while staying up-to-date with the latest 2025 R2 features like SQL queries for Iceberg and event notifications.

Key Features

01Optimization patterns for metadata management and HTTP cache-control headers.

02Advanced multipart upload management for handling files larger than 100MB.

03Detailed CORS configuration guidance for browser-based storage access.

04Secure server-side presigned URL generation patterns using aws4fetch.

0591 GitHub stars

06Comprehensive Workers API support for put, get, head, list, and delete operations.

Use Cases

01Building scalable media upload pipelines with direct-to-bucket browser uploads.

02Implementing secure, authenticated file sharing services using temporary presigned URLs.

03Managing large asset distributions with zero egress fees and edge caching.

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add jezweb/claude-skills cloudflare-r2

For use in Claude.ai and ChatGPT

Download Skill