R2 Object Storage

Store and retrieve objects at scale using Cloudflare’s S3-compatible object storage.

When to Use

• File uploads (images, videos, documents)
• AI assets and model artifacts
• Image and media asset storage
• Structured data (JSON, CSV, logs)
• User-facing uploads and downloads
• Static asset hosting
• Backup and archival storage
• S3-compatible workflows with existing tools

FIRST: Create R2 Bucket

# Create bucket
wrangler r2 bucket create my-bucket

# Create with location hint
wrangler r2 bucket create my-bucket --location wnam

# List buckets
wrangler r2 bucket list

Quick Reference

Wrangler Configuration

// wrangler.jsonc
{
  "name": "my-worker",
  "main": "src/index.ts",
  "compatibility_date": "2026-01-01",
  "r2_buckets": [
    {
      "binding": "BUCKET",
      "bucket_name": "my-bucket"
    }
  ]
}

TypeScript Types (run wrangler types to generate):

export interface Env {
  BUCKET: R2Bucket;
}

Basic Upload and Download

import { R2Bucket } from "@cloudflare/workers-types";

export interface Env {
  BUCKET: R2Bucket;
}

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const url = new URL(request.url);
    const key = url.pathname.slice(1); // Remove leading /

    // Upload
    if (request.method === "PUT") {
      await env.BUCKET.put(key, request.body, {
        httpMetadata: {
          contentType: request.headers.get("content-type") || "application/octet-stream",
        },
      });
      return new Response("Uploaded", { status: 201 });
    }

    // Download
    if (request.method === "GET") {
      const object = await env.BUCKET.get(key);
      
      if (!object) {
        return new Response("Not found", { status: 404 });
      }

      return new Response(object.body, {
        headers: {
          "Content-Type": object.httpMetadata?.contentType || "application/octet-stream",
          "ETag": object.httpEtag,
          "Cache-Control": object.httpMetadata?.cacheControl || "public, max-age=3600",
        },
      });
    }

    // Delete
    if (request.method === "DELETE") {
      await env.BUCKET.delete(key);
      return new Response("Deleted", { status: 204 });
    }

    return new Response("Method not allowed", { status: 405 });
  },
};

Multipart Form Upload Handler

Handle file uploads from HTML forms or multipart requests.

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    if (request.method !== "POST") {
      return new Response("Method not allowed", { status: 405 });
    }

    const formData = await request.formData();
    const file = formData.get("file") as File;

    if (!file) {
      return new Response("No file provided", { status: 400 });
    }

    // Generate unique key
    const key = `uploads/${crypto.randomUUID()}-${file.name}`;

    // Upload to R2
    await env.BUCKET.put(key, file.stream(), {
      httpMetadata: {
        contentType: file.type,
      },
      customMetadata: {
        originalName: file.name,
        uploadedAt: new Date().toISOString(),
      },
    });

    return Response.json({
      success: true,
      key,
      url: `/files/${key}`,
    });
  },
};

List Objects with Pagination

async function listAllObjects(
  bucket: R2Bucket,
  prefix: string = ""
): Promise<R2Object[]> {
  const objects: R2Object[] = [];
  let cursor: string | undefined;

  do {
    const listed = await bucket.list({
      prefix,
      cursor,
      limit: 1000,
    });

    objects.push(...listed.objects);
    cursor = listed.truncated ? listed.cursor : undefined;
  } while (cursor);

  return objects;
}

// Usage
export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const url = new URL(request.url);
    const prefix = url.searchParams.get("prefix") || "";

    const objects = await listAllObjects(env.BUCKET, prefix);

    return Response.json({
      count: objects.length,
      objects: objects.map((obj) => ({
        key: obj.key,
        size: obj.size,
        uploaded: obj.uploaded,
      })),
    });
  },
};

Conditional Operations (ETags)

Use ETags for conditional reads/writes to prevent race conditions.

// Conditional write (only if not modified)
const existingObject = await env.BUCKET.head("config.json");

if (existingObject) {
  // Update only if ETag matches
  await env.BUCKET.put("config.json", newData, {
    httpMetadata: {
      contentType: "application/json",
    },
    onlyIf: {
      etagMatches: existingObject.httpEtag,
    },
  });
}

// Conditional read (If-None-Match)
const object = await env.BUCKET.get("image.jpg", {
  onlyIf: {
    etagDoesNotMatch: cachedEtag,
  },
});

if (object === null) {
  // Object not modified - return 304
  return new Response(null, {
    status: 304,
    headers: { "ETag": cachedEtag },
  });
}

Custom Metadata

Store application-specific metadata alongside objects.

// Store with custom metadata
await env.BUCKET.put("document.pdf", pdfData, {
  httpMetadata: {
    contentType: "application/pdf",
  },
  customMetadata: {
    userId: "user-123",
    documentType: "invoice",
    version: "2",
    tags: "finance,2024",
  },
});

// Read metadata without downloading body
const object = await env.BUCKET.head("document.pdf");
console.log(object.customMetadata?.userId); // "user-123"

Range Requests (Partial Downloads)

Efficiently download portions of large files.

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const key = new URL(request.url).pathname.slice(1);
    const rangeHeader = request.headers.get("range");

    if (rangeHeader) {
      // Parse range: "bytes=0-1023"
      const match = rangeHeader.match(/bytes=(\d+)-(\d*)/);
      if (match) {
        const start = parseInt(match[1], 10);
        const end = match[2] ? parseInt(match[2], 10) : undefined;

        const object = await env.BUCKET.get(key, {
          range: { offset: start, length: end ? end - start + 1 : undefined },
        });

        if (!object) {
          return new Response("Not found", { status: 404 });
        }

        return new Response(object.body, {
          status: 206,
          headers: {
            "Content-Type": object.httpMetadata?.contentType || "application/octet-stream",
            "Content-Range": `bytes ${start}-${end || object.size - 1}/${object.size}`,
            "Content-Length": object.size.toString(),
          },
        });
      }
    }

    // Regular full download
    const object = await env.BUCKET.get(key);
    if (!object) {
      return new Response("Not found", { status: 404 });
    }

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

AWS SDK Integration (S3 Compatible)

R2 is fully compatible with the AWS S3 API. Use the official AWS SDK v3.

Install dependencies:

npm install @aws-sdk/client-s3 @aws-sdk/s3-request-presigner

wrangler.jsonc (add Node.js compatibility):

{
  "compatibility_flags": ["nodejs_compat_v2"],
  "r2_buckets": [
    { "binding": "BUCKET", "bucket_name": "my-bucket" }
  ]
}

Using AWS SDK:

import { S3Client, PutObjectCommand, GetObjectCommand } from "@aws-sdk/client-s3";
import { getSignedUrl } from "@aws-sdk/s3-request-presigner";

export interface Env {
  BUCKET: R2Bucket;
  R2_ACCESS_KEY_ID: string;
  R2_SECRET_ACCESS_KEY: string;
  R2_ACCOUNT_ID: string;
}

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    // Create S3 client
    const s3 = new S3Client({
      region: "auto",
      endpoint: `https://${env.R2_ACCOUNT_ID}.r2.cloudflarestorage.com`,
      credentials: {
        accessKeyId: env.R2_ACCESS_KEY_ID,
        secretAccessKey: env.R2_SECRET_ACCESS_KEY,
      },
    });

    // Upload using S3 API
    await s3.send(
      new PutObjectCommand({
        Bucket: "my-bucket",
        Key: "file.txt",
        Body: "Hello R2",
        ContentType: "text/plain",
      })
    );

    // Generate presigned URL (valid for 1 hour)
    const command = new GetObjectCommand({
      Bucket: "my-bucket",
      Key: "file.txt",
    });
    const signedUrl = await getSignedUrl(s3, command, { expiresIn: 3600 });

    return Response.json({ signedUrl });
  },
};

Note: Using the native R2Bucket binding is more efficient than AWS SDK for basic operations. Use AWS SDK when you need presigned URLs or have existing S3 tooling.

Presigned URLs for Direct Uploads

Allow clients to upload directly to R2 without going through your Worker.

import { S3Client, PutObjectCommand } from "@aws-sdk/client-s3";
import { getSignedUrl } from "@aws-sdk/s3-request-presigner";

export interface Env {
  R2_ACCESS_KEY_ID: string;
  R2_SECRET_ACCESS_KEY: string;
  R2_ACCOUNT_ID: string;
}

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const url = new URL(request.url);

    // Generate presigned upload URL
    if (url.pathname === "/upload-url") {
      const filename = url.searchParams.get("filename");
      if (!filename) {
        return new Response("Missing filename", { status: 400 });
      }

      const s3 = new S3Client({
        region: "auto",
        endpoint: `https://${env.R2_ACCOUNT_ID}.r2.cloudflarestorage.com`,
        credentials: {
          accessKeyId: env.R2_ACCESS_KEY_ID,
          secretAccessKey: env.R2_SECRET_ACCESS_KEY,
        },
      });

      const key = `uploads/${crypto.randomUUID()}-${filename}`;
      const command = new PutObjectCommand({
        Bucket: "my-bucket",
        Key: key,
      });

      const signedUrl = await getSignedUrl(s3, command, { expiresIn: 300 }); // 5 minutes

      return Response.json({
        uploadUrl: signedUrl,
        key,
      });
    }

    return new Response("Not found", { status: 404 });
  },
};

Client-side usage:

// 1. Get presigned URL from your Worker
const response = await fetch("/upload-url?filename=photo.jpg");
const { uploadUrl, key } = await response.json();

// 2. Upload file directly to R2
const file = document.querySelector('input[type="file"]').files[0];
await fetch(uploadUrl, {
  method: "PUT",
  body: file,
  headers: {
    "Content-Type": file.type,
  },
});

// 3. File is now available at key in R2

Multipart Upload for Large Files

For files larger than 100MB, use multipart uploads:

// Initiate multipart upload
const multipartUpload = await env.BUCKET.createMultipartUpload(key, {
  httpMetadata: { contentType: "application/zip" }
});

const uploadedParts: R2UploadedPart[] = [];
const chunkSize = 10 * 1024 * 1024; // 10MB chunks

// Upload parts
for (let offset = 0; offset < data.byteLength; offset += chunkSize) {
  const chunk = data.slice(offset, Math.min(offset + chunkSize, data.byteLength));
  const part = await multipartUpload.uploadPart(partNumber++, chunk);
  uploadedParts.push(part);
}

// Complete upload
const object = await multipartUpload.complete(uploadedParts);

See references/operations.md for complete multipart upload patterns

Detailed References

• references/operations.md – Complete API reference, conditional operations, streaming, error handling
• references/s3-compat.md – S3 API compatibility, AWS SDK patterns, presigned URLs, migration guide
• references/limits.md – Storage limits, rate limits, Workers integration limits, best practices
• references/testing.md – Vitest integration, mocking R2, multipart uploads, test isolation

Best Practices

1. Set appropriate Content-Type: Always specify httpMetadata.contentType for proper browser handling
2. Use unique keys: Prefix with UUIDs or timestamps to avoid collisions
3. Leverage custom metadata: Store searchable metadata without downloading objects
4. Use ETags for consistency: Implement conditional operations for race condition prevention
5. Stream large uploads: Use multipart uploads for files > 100MB
6. Cache control headers: Set appropriate cacheControl in httpMetadata
7. Use presigned URLs for direct uploads: Reduce Worker bandwidth and latency
8. List with pagination: Always handle truncated results when listing objects
9. Use R2Bucket binding by default: Only use AWS SDK when you need presigned URLs or S3-specific features
10. Handle 404s gracefully: bucket.get() returns null when object doesn’t exist

Common Patterns

See references/operations.md for complete examples including:

• Image upload and optimization with metadata
• Structured data storage (JSON profiles)
• Backup and archival patterns
• Streaming large files
• Conditional operations with ETags