Cloudflare R2

Cloudflare R2 Object Storage

Complete knowledge domain for Cloudflare R2 - S3-compatible object storage on Cloudflare's global network.

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Auto-Trigger Keywords

Primary Keywords

• r2 storage
• cloudflare r2
• r2 upload
• r2 download
• r2 bucket
• r2 binding
• object storage
• r2 api
• r2 workers

Secondary Keywords

• s3 compatible
• r2 cors
• presigned urls
• multipart upload
• r2 get
• r2 put
• r2 delete
• r2 list
• file upload
• asset storage
• image storage
• r2 metadata
• custom metadata
• http metadata
• r2 wrangler

Error-Based Keywords

• R2_ERROR
• CORS error r2
• presigned url failed
• multipart upload failed
• r2 quota exceeded
• content-type missing
• r2 bucket not found
• r2 access denied
• bulk delete failed

Framework Integration Keywords

• r2 hono
• r2 workers api
• r2 cloudflare workers
• wrangler r2
• r2 bindings

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What This Skill Does

This skill provides complete R2 knowledge including:

• ✅ R2 Workers API - put(), get(), head(), delete(), list()
• ✅ Multipart Uploads - For files >100MB with resumable uploads
• ✅ Presigned URLs - Client-side direct uploads/downloads
• ✅ CORS Configuration - Browser access to R2 buckets
• ✅ HTTP Metadata - Content-Type, Cache-Control, Content-Disposition
• ✅ Custom Metadata - User-defined key-value pairs
• ✅ Bucket Configuration - wrangler.jsonc setup and bindings
• ✅ Error Handling - Retry strategies and common errors
• ✅ Performance Optimization - Batch operations, range requests, caching

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Known Issues Prevented

Issue	Description	Prevention
CORS errors	Browser uploads fail	Configure CORS before browser access
Binary downloads	Files download as binary blob	Always set contentType on upload
Presigned URL security	URLs never expire	Set X-Amz-Expires parameter
Multipart limits	Upload fails with large files	Use 5MB-100MB parts, max 10,000 parts
Bulk delete limits	Deleting >1000 keys fails	Chunk into batches of 1000
Metadata overflow	Custom metadata exceeds 2KB	Keep total metadata under 2KB

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When to Use This Skill

✅ Use this skill when:

• Storing user uploads (images, documents, videos)
• Serving static assets (CSS, JS, images)
• Building file management systems
• Implementing direct client uploads
• Setting up CORS for browser access
• Generating presigned URLs
• Uploading large files (multipart)
• Migrating from S3 to R2

❌ When NOT to use:

• You need a relational database (use cloudflare-d1)
• You need key-value storage (use cloudflare-kv)
• Files are <1KB (KV might be better)
• You need vector search (use cloudflare-vectorize)

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Quick Example

import { Hono } from 'hono';

type Bindings = {
  MY_BUCKET: R2Bucket;
};

const app = new Hono<{ Bindings: Bindings }>();

// Upload file
app.put('/upload/:filename', async (c) => {
  const filename = c.req.param('filename');
  const body = await c.req.arrayBuffer();

  const object = await c.env.MY_BUCKET.put(filename, body, {
    httpMetadata: {
      contentType: c.req.header('content-type') || 'application/octet-stream',
    },
  });

  return c.json({
    success: true,
    key: object.key,
    size: object.size,
  });
});

// Download file
app.get('/download/:filename', async (c) => {
  const filename = c.req.param('filename');
  const object = await c.env.MY_BUCKET.get(filename);

  if (!object) {
    return c.json({ error: 'Not found' }, 404);
  }

  return new Response(object.body, {
    headers: {
      'Content-Type': object.httpMetadata?.contentType || 'application/octet-stream',
      'ETag': object.httpEtag,
    },
  });
});

export default app;

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Files Included

• SKILL.md - Complete R2 knowledge domain
• templates/wrangler-r2-config.jsonc - R2 binding configuration
• templates/r2-simple-upload.ts - Basic upload/download Worker
• templates/r2-multipart-upload.ts - Multipart upload Worker
• templates/r2-presigned-urls.ts - Presigned URL generator
• templates/r2-cors-config.json - CORS policy examples
• reference/workers-api.md - Complete Workers API reference
• reference/s3-compatibility.md - S3 API compatibility notes
• reference/common-patterns.md - Common R2 patterns

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Dependencies

• cloudflare-worker-base - For Hono + Vite + Worker setup
• wrangler - For R2 bucket management
• aws4fetch (optional) - For presigned URL generation

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Production Status

✅ Production Ready

This skill is based on:

• Official Cloudflare R2 documentation
• Cloudflare Workers SDK examples
• Production-tested patterns
• Latest package versions (verified 2025-10-21)

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Related Skills

• cloudflare-worker-base - Base Worker setup with Hono
• cloudflare-d1 - Serverless SQLite database
• cloudflare-kv - Key-value storage
• cloudflare-workers-ai - AI inference on Workers

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Last Updated: 2025-10-21 Status: Production Ready ✅ Maintainer: Claude Skills Maintainers | maintainers@example.com