Error: CORS Error DynamoDB

A CORS error means the browser blocked access to a cross-origin response. First identify the failing URL: a frontend calling your API needs CORS on that API, not a table setting in DynamoDB.

1. Use the browser Network panel to inspect the OPTIONS preflight and the actual request. Check the origin, requested method, headers and response status.
2. For API Gateway HTTP APIs, configure CORS on the API. For REST APIs, configure preflight and the appropriate response headers; proxy integrations must return the actual response headers.
3. Include required CORS headers on error responses too. An authentication or server failure can otherwise appear as a CORS problem.
4. For local development, configure CORS on the local service or proxy and use the correct scheme and port. An HTTPS page calling an HTTP endpoint can also encounter mixed-content restrictions.

Allow only intended origins, methods and headers. Credentialed browser requests cannot use a wildcard Allow-Origin response. Do not add Access-Control-Allow-Origin as a request header or disable browser security as a fix.

If calling DynamoDB directly from browser code, use a supported SDK with temporary, scoped credentials. Never embed permanent AWS secrets in the frontend. A backend can keep DynamoDB access and credentials on the server.

See application security and AWS documentation.