Error: DynamoDB validation error

A DynamoDB validation error means the request violates an API or data constraint. The full message identifies the failing field. There is no general 1 KB attribute-value limit, and new non-key attributes do not need to be added to a table schema.

• Check the complete primary key and the defined types of table and index key attributes. Empty key values are invalid.
• Keep the resulting item within 400 KB, including names and values. Number precision, nesting, and expression limits are separate constraints.
• Reject empty sets and invalid numeric values. Empty non-key strings, lists, and maps are allowed.
• Use the correct request shape for the SDK layer and define only the expression placeholders the request uses.
• PutItem with an existing primary key replaces the existing item unless a condition rejects it. An existing key is not by itself a validation error.

An access denial or throttling exception requires a different fix. Preserve the exact error and sanitized input shape, correct the invalid request, and then resend it. Adding retries or increasing capacity cannot make malformed data valid.

See attribute validation and AWS documentation.