--- description: Configure the AWS SDK for JavaScript v2 to work with Cloudflare R2. title: aws-sdk-js image: https://developers.cloudflare.com/og-docs.png --- [Skip to content](#main-content) > 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. # aws-sdk-js Last updated Aug 24, 2026|Copy as Markdown|[View as Markdown](https://e8aee267.previews.developers.cloudflare.com/r2/examples/aws/aws-sdk-js/index.md)|[Agent setup](https://e8aee267.previews.developers.cloudflare.com/agent-setup/) You must [generate an Access Key](https://e8aee267.previews.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. If you are interested in the newer version of the AWS JavaScript SDK visit this [dedicated aws-sdk-js-v3 example page](https://e8aee267.previews.developers.cloudflare.com/r2/examples/aws/aws-sdk-js-v3/). JavaScript or TypeScript users may continue to use the [aws-sdk ↗](https://www.npmjs.com/package/aws-sdk) npm package as per normal. You must pass in the R2 configuration credentials when instantiating your `S3` service client: ```ts import S3 from "aws-sdk/clients/s3.js"; const s3 = new S3({ // Provide your Cloudflare account ID endpoint: `https://${ACCOUNT_ID}.r2.cloudflarestorage.com`, // Retrieve your S3 API credentials for your R2 bucket via API tokens (see: https://developers.cloudflare.com/r2/api/tokens) accessKeyId: `${ACCESS_KEY_ID}`, secretAccessKey: `${SECRET_ACCESS_KEY}`, signatureVersion: "v4", }); console.log(await s3.listBuckets().promise()); //=> { //=> 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.listObjects({ Bucket: "my-bucket" }).promise()); //=> { //=> IsTruncated: false, //=> Name: 'my-bucket', //=> CommonPrefixes: [], //=> MaxKeys: 1000, //=> Contents: [ //=> { //=> Key: 'cat.png', //=> LastModified: 2022-05-07T02:50:45.616Z, //=> ETag: '"c4da329b38467509049e615c11b0c48a"', //=> ChecksumAlgorithm: [], //=> Size: 751832, //=> Owner: [Object] //=> }, //=> { //=> Key: 'todos.txt', //=> LastModified: 2022-05-07T21:37:17.150Z, //=> ETag: '"29d911f495d1ba7cb3a4d7d15e63236a"', //=> ChecksumAlgorithm: [], //=> Size: 279, //=> Owner: [Object] //=> } //=> ] //=> } ``` ## Generate presigned URLs You can also generate presigned links that can be used to share public read or write access to a bucket temporarily. ```ts // Use the expires property to determine how long the presigned link is valid. console.log( await s3.getSignedUrlPromise("getObject", { Bucket: "my-bucket", Key: "dog.png", Expires: 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 s3.getSignedUrlPromise("putObject", { Bucket: "my-bucket", Key: "dog.png", Expires: 3600, ContentType: "image/png", }), ); ``` ```sh https://my-bucket..r2.cloudflarestorage.com/dog.png?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=&X-Amz-Date=&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature= https://my-bucket..r2.cloudflarestorage.com/dog.png?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=&X-Amz-Date=&X-Amz-Expires=3600&X-Amz-SignedHeaders=content-type%3Bhost&X-Amz-Signature= ``` 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. ```sh 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 presigned URL parameters. The upload will fail if the client sends a different `Content-Type` header. 2. **Configuring CORS**: Set up [CORS rules](https://e8aee267.previews.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: ```json [ { "AllowedOrigins": ["https://example.com"], "AllowedMethods": ["PUT"], "AllowedHeaders": ["Content-Type"], "ExposeHeaders": ["ETag"], "MaxAgeSeconds": 3600 } ] ``` Then generate a presigned URL with a Content-Type restriction: ```ts const putUrl = await s3.getSignedUrlPromise("putObject", { Bucket: "my-bucket", Key: "user-upload.png", Expires: 3600, ContentType: "image/png", }); ``` 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) Was this helpful? YesNo ## On this page [![](https://e8aee267.previews.developers.cloudflare.com/_astro/logo.te5VL_aD.svg)Docs](https://e8aee267.previews.developers.cloudflare.com/) ```json {"@context":"https://schema.org","@type":"TechArticle","@id":"https://developers.cloudflare.com/r2/examples/aws/aws-sdk-js/#page","headline":"aws-sdk-js · Cloudflare R2 docs","description":"Configure the AWS SDK for JavaScript v2 to work with Cloudflare R2.","url":"https://developers.cloudflare.com/r2/examples/aws/aws-sdk-js/","inLanguage":"en","image":"https://developers.cloudflare.com/og-docs.png","dateModified":"2026-08-24","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/"}} ```