# Cloudflare R2 (/docs/adapters/r2)



<ComponentPreview name="r2-presigned" />

R2 implements the S3 API, so the browser code is identical to S3, `r2Adapter` is an
alias of `s3Adapter`. The difference is on the server.

## Server [#server]

```ts title="app/api/upload/route.ts"
import { createUploadRoute, r2Storage } from "@uploadcn/server"

export const { POST } = createUploadRoute({
  storage: r2Storage({
    accountId: process.env.R2_ACCOUNT_ID!,
    bucket: process.env.R2_BUCKET!,
    accessKeyId: process.env.R2_ACCESS_KEY_ID!,
    secretAccessKey: process.env.R2_SECRET_ACCESS_KEY!,
    // A custom domain or r2.dev URL for reading objects:
    publicUrl: process.env.R2_PUBLIC_URL,
  }),
})
```

`r2Storage` uses `https://<account>.r2.cloudflarestorage.com`, region `auto` and
path-style URLs. For jurisdiction-restricted buckets pass `jurisdiction: "eu"`.

`@uploadcn/server` signs with Web Crypto, so the same route runs on Cloudflare Workers.

## CORS [#cors]

In the R2 dashboard, under **Settings → CORS policy**:

```json
[
  {
    "AllowedOrigins": ["https://your-app.com"],
    "AllowedMethods": ["PUT"],
    "AllowedHeaders": ["content-type"],
    "ExposeHeaders": ["ETag"]
  }
]
```

## Client [#client]

```ts
import { r2Adapter } from "@uploadcn/core"

const adapter = r2Adapter({ endpoint: "/api/upload" })
```