How to Troubleshoot CORS Issues in API Gateway

If you encounter CORS (Cross-Origin Resource Sharing) errors when making API requests, there are several common causes and solutions to check: Common CORS Error Messages "No 'Access-Control-Allow-Origin' header is present on the requested resource" "Request header field is not allowed by Access-Control-Allow-Headers in preflight response" Troubleshooting Steps Clear Browser Cache

• First try clearing your browser cache as CORS settings may be cached locally. Verify API Gateway CORS Configuration

• Ensure your API Gateway CORS settings include: Correct origin domains in Access-Control-Allow-Origin All required custom headers in Access-Control-Allow-Headers (e.g., x-tenant-id) Check Deployment Status

• After making changes to API Gateway configurations: Ensure you redeploy the API Gateway for changes to take effect Verify the correct branch/configuration is deployed to your environment Environment Testing

• When making CORS configuration changes: Test changes in development environment first Only promote to other environments (sandbox, production) after successful testing Best Practice: Always test CORS changes in development environment before applying to sandbox or production environments.