--- title: aws-sdk-js-v3 description: Configure the AWS SDK for JavaScript v3 to work with Cloudflare R2. image: https://developers.cloudflare.com/dev-products-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/r2/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # aws-sdk-js-v3 You must [generate an Access Key](https://developers.cloudflare.com/r2/api/tokens/) before getting started. All examples will utilize `access_key_id` and `access_key_secret` variables which represent the **Access Key ID** and **Secret Access Key** values you generated. JavaScript or TypeScript users may continue to use the [@aws-sdk/client-s3 ↗](https://www.npmjs.com/package/@aws-sdk/client-s3) npm package as per normal. You must pass in the R2 configuration credentials when instantiating your `S3` service client. Note Currently, you cannot use AWS S3-compatible API while developing locally via `wrangler dev`. TypeScript ``` import { S3Client, ListBucketsCommand, ListObjectsV2Command, GetObjectCommand, PutObjectCommand,} from "@aws-sdk/client-s3"; const S3 = new S3Client({ region: "auto", // Required by SDK but not used by R2 // Provide your Cloudflare account ID endpoint: `https://${ACCOUNT_ID}.r2.cloudflarestorage.com`, // Retrieve your S3 API credentials for your R2 bucket via API tokens (see: https://developers.cloudflare.com/r2/api/tokens) credentials: { accessKeyId: ACCESS_KEY_ID, secretAccessKey: SECRET_ACCESS_KEY, },}); console.log(await S3.send(new ListBucketsCommand({})));// {// '$metadata': {// httpStatusCode: 200,// requestId: undefined,// extendedRequestId: undefined,// cfId: undefined,// attempts: 1,// totalRetryDelay: 0// },// Buckets: [// { Name: 'user-uploads', CreationDate: 2022-04-13T21:23:47.102Z },// { Name: 'my-bucket', CreationDate: 2022-05-07T02:46:49.218Z }// ],// Owner: {// DisplayName: '...',// ID: '...'// }// } console.log( await S3.send(new ListObjectsV2Command({ Bucket: "my-bucket" })),);// {// '$metadata': {// httpStatusCode: 200,// requestId: undefined,// extendedRequestId: undefined,// cfId: undefined,// attempts: 1,// totalRetryDelay: 0// },// CommonPrefixes: undefined,// Contents: [// {// Key: 'cat.png',// LastModified: 2022-05-07T02:50:45.616Z,// ETag: '"c4da329b38467509049e615c11b0c48a"',// ChecksumAlgorithm: undefined,// Size: 751832,// StorageClass: 'STANDARD',// Owner: undefined// },// {// Key: 'todos.txt',// LastModified: 2022-05-07T21:37:17.150Z,// ETag: '"29d911f495d1ba7cb3a4d7d15e63236a"',// ChecksumAlgorithm: undefined,// Size: 279,// StorageClass: 'STANDARD',// Owner: undefined// }// ],// ContinuationToken: undefined,// Delimiter: undefined,// EncodingType: undefined,// IsTruncated: false,// KeyCount: 8,// MaxKeys: 1000,// Name: 'my-bucket',// NextContinuationToken: undefined,// Prefix: undefined,// StartAfter: undefined// } ``` ## Generate presigned URLs You can also generate presigned links that can be used to share public read or write access to a bucket temporarily. TypeScript ``` import { getSignedUrl } from "@aws-sdk/s3-request-presigner"; // Use the expiresIn property to determine how long the presigned link is valid.console.log( await getSignedUrl( S3, new GetObjectCommand({ Bucket: "my-bucket", Key: "dog.png" }), { expiresIn: 3600 }, ),);// You can also create links for operations such as PutObject to allow temporary write access to a specific key.// Specify ContentType to restrict uploads to a specific file type.console.log( await getSignedUrl( S3, new PutObjectCommand({ Bucket: "my-bucket", Key: "dog.png", ContentType: "image/png", }), { expiresIn: 3600 }, ),); ``` ``` https://my-bucket..r2.cloudflarestorage.com/dog.png?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=&X-Amz-Date=&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=&x-id=GetObjecthttps://my-bucket..r2.cloudflarestorage.com/dog.png?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=&X-Amz-Date=&X-Amz-Expires=3600&X-Amz-SignedHeaders=content-type%3Bhost&X-Amz-Signature=&x-id=PutObject ``` You can use the link generated by the `PutObject` example to upload to the specified bucket and key, until the presigned link expires. When using a presigned URL with `ContentType`, the client must include a matching `Content-Type` header in the request. Terminal window ``` curl -X PUT "https://my-bucket..r2.cloudflarestorage.com/dog.png?X-Amz-Algorithm=..." \ -H "Content-Type: image/png" \ --data-binary @dog.png ``` ## Restrict uploads with CORS and Content-Type When generating presigned URLs for uploads, you can limit abuse and misuse by: 1. **Restricting Content-Type**: Specify the allowed content type in the `PutObjectCommand`. The upload will fail if the client sends a different `Content-Type` header. 2. **Configuring CORS**: Set up [CORS rules](https://developers.cloudflare.com/r2/buckets/cors/#add-cors-policies-from-the-dashboard) on your bucket to control which origins can upload files. Configure CORS via the [Cloudflare dashboard ↗](https://dash.cloudflare.com/?to=/:account/r2/overview) by adding a JSON policy to your bucket settings: ``` [ { "AllowedOrigins": ["https://example.com"], "AllowedMethods": ["PUT"], "AllowedHeaders": ["Content-Type"], "ExposeHeaders": ["ETag"], "MaxAgeSeconds": 3600 }] ``` Then generate a presigned URL with a Content-Type restriction: TypeScript ``` const putUrl = await getSignedUrl( S3, new PutObjectCommand({ Bucket: "my-bucket", Key: "dog.png", ContentType: "image/png", }), { expiresIn: 3600 },); ``` When a client uses this presigned URL, they must: * Make the request from an allowed origin (enforced by CORS) * Include the `Content-Type: image/png` header (enforced by the signature) ```json {"@context":"https://schema.org","@type":"TechArticle","@id":"https://developers.cloudflare.com/r2/examples/aws/aws-sdk-js-v3/#page","headline":"aws-sdk-js-v3 · Cloudflare R2 docs","description":"Configure the AWS SDK for JavaScript v3 to work with Cloudflare R2.","url":"https://developers.cloudflare.com/r2/examples/aws/aws-sdk-js-v3/","inLanguage":"en","image":"https://developers.cloudflare.com/dev-products-preview.png","dateModified":"2026-04-21","publisher":{"@type":"Organization","name":"Cloudflare","url":"https://www.cloudflare.com/"},"isPartOf":{"@type":"WebSite","@id":"https://developers.cloudflare.com/#website","name":"Cloudflare Docs","url":"https://developers.cloudflare.com/"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/r2/","name":"R2"}},{"@type":"ListItem","position":3,"item":{"@id":"/r2/examples/","name":"Examples"}},{"@type":"ListItem","position":4,"item":{"@id":"/r2/examples/aws/","name":"S3 SDKs"}},{"@type":"ListItem","position":5,"item":{"@id":"/r2/examples/aws/aws-sdk-js-v3/","name":"aws-sdk-js-v3"}}]} ```