Cloud Bucket CORS Generator

Generate CORS policies for AWS S3, Cloudflare R2, and Google Cloud Storage. Visual configuration with real-time preview - no more frustrating JSON/XML editing.

Select Cloud Provider

CORS Configuration

Allowed HTTP Methods

Allowed Origins

Allowed Headers

Additional Settings

How long results of a preflight request can be cached (0-86400)

Headers accessible to client-side JavaScript

Generated Policy

// Configure your CORS settings to see the generated policy

How to Apply

Select a cloud provider and configure your CORS settings to see specific instructions.

Why Use This Tool?

🎯 Visual Configuration

No more manual JSON/XML editing. Check boxes and fill forms to generate perfect CORS policies.

☁️ Multi-Cloud Support

Generate policies for AWS S3, Cloudflare R2, and Google Cloud Storage with correct syntax.

⚡ Real-time Preview

See your CORS policy update instantly as you change settings. Copy or download with one click.

Common Use Cases

Static Website Hosting

API File Upload

Development Environment

Public API

S3 CORS Policy Generator Guide

What is S3 CORS Policy?

CORS (Cross-Origin Resource Sharing) is a security feature that allows web applications to make requests to different domains. An S3 CORS policy controls which websites can access files in your S3 bucket, preventing unauthorized access while enabling legitimate cross-origin requests.

Why Do You Need S3 CORS Configuration?

Without proper CORS configuration, browsers block cross-origin requests to your S3 bucket, causing errors in your web applications. Common scenarios requiring S3 CORS include:

  • JavaScript applications loading assets from S3
  • Web fonts hosted on S3
  • API endpoints served from S3
  • Static site generators with S3 backends
  • CDN integrations with S3 origins

How to Use This S3 CORS Policy Generator

1

Select Your Cloud Provider

Choose between AWS S3, Cloudflare R2, or Google Cloud Storage. Each provider has slightly different policy formats.

2

Configure HTTP Methods

Select which HTTP methods (GET, POST, PUT, DELETE, etc.) to allow. Only enable methods your application actually needs.

3

Set Allowed Origins

Specify which domains can access your S3 bucket. Use "*" for public access or specific domains for better security.

4

Configure Headers and Cache

Set allowed headers and cache duration. Longer cache times improve performance but reduce flexibility.

5

Copy and Apply Policy

Copy the generated policy and apply it to your S3 bucket using AWS Console, CLI, or SDK.

Common S3 CORS Policy Examples

Static Website Hosting

For static websites hosted on S3:

  • • Methods: GET, HEAD
  • • Origins: Your website domain
  • • Headers: Content-Type, Authorization

JavaScript Application

For web apps with API calls:

  • • Methods: GET, POST, PUT, DELETE
  • • Origins: Multiple allowed domains
  • • Headers: All custom headers

Public Asset Server

For publicly accessible assets:

  • • Methods: GET, HEAD
  • • Origins: * (any domain)
  • • Headers: Content-Type

S3 CORS Policy Best Practices

Security Recommendations:

  • Use specific domains instead of "*" when possible
  • Only enable HTTP methods your application needs
  • Set reasonable cache durations (1 hour to 1 day)
  • Regularly review and update CORS policies
  • Test policies in staging before production

How to Apply S3 CORS Policy

Using AWS Console:

  1. Navigate to your S3 bucket
  2. Click "Permissions" tab
  3. Scroll to "Cross-origin resource sharing (CORS)"
  4. Click "Edit" and paste your policy
  5. Click "Save changes"

Using AWS CLI:

aws s3api put-bucket-cors --bucket your-bucket-name --cors-configuration file://cors-policy.json

Troubleshooting S3 CORS Issues

CORS Error: "No 'Access-Control-Allow-Origin' header"

Your CORS policy isn't matching the request. Check allowed origins and methods.

CORS Error: "Multiple origins not allowed"

Your policy has conflicting rules. Ensure each rule has distinct origins.

CORS Error: "Method not allowed"

The HTTP method isn't in your allowed methods list. Add it to your policy.