CORS on other S3-compatible providers

Any storage that speaks the S3 API supports the same CORS configuration shape. If your provider isn’t covered by a dedicated page in this section yet, this generic recipe should still work.

The policy

[
  {
    "AllowedOrigins": [
      "https://studio.relyn.app",
      "http://localhost:5173"
    ],
    "AllowedMethods": ["GET", "PUT", "HEAD", "POST", "DELETE"],
    "AllowedHeaders": ["*"],
    "ExposeHeaders": ["ETag"],
    "MaxAgeSeconds": 3600
  }
]

Replace https://studio.relyn.app with your studio URL if you self-host Relyn. Drop the localhost line if you don’t develop Relyn locally.

How to apply it

Each provider exposes this a little differently. Look for one of:

1. A bucket settings tab in the provider’s dashboard with a “CORS Policy”, “CORS Configuration”, or “Cross-Origin” section. Paste the JSON there.

2. An S3-compatible CLI. Most providers respond to:

   aws s3api put-bucket-cors \
     --endpoint-url https://YOUR-PROVIDER-ENDPOINT \
     --bucket YOUR_BUCKET \
     --cors-configuration '{ "CORSRules": [ ... ] }'

   The body wraps the rules in {"CORSRules": [...]} — same content, slightly different shape.

3. An API call. The S3 PUT Bucket CORS operation:

   PUT /?cors HTTP/1.1
   Host: your-provider-endpoint
   Content-MD5: ...
   Authorization: AWS4-HMAC-SHA256 ...
   Content-Type: application/xml
   
   <CORSConfiguration>
     <CORSRule>
       <AllowedOrigin>https://studio.relyn.app</AllowedOrigin>
       <AllowedMethod>GET</AllowedMethod>
       <AllowedMethod>PUT</AllowedMethod>
       <AllowedMethod>HEAD</AllowedMethod>
       <AllowedMethod>POST</AllowedMethod>
       <AllowedMethod>DELETE</AllowedMethod>
       <AllowedHeader>*</AllowedHeader>
       <ExposeHeader>ETag</ExposeHeader>
       <MaxAgeSeconds>3600</MaxAgeSeconds>
     </CORSRule>
   </CORSConfiguration>

Verify

In Relyn, open the bucket and click Diagnose. Relyn runs an OPTIONS preflight against your bucket endpoint and confirms the policy works.

Tell us which provider

If you’re setting Relyn up on a provider that isn’t yet listed in this section and you’d like a dedicated page (with their exact dashboard steps), drop a note to hello@relyn.app — we add guides based on what real users connect.