DynamoDB Attribute Types

Atomic Types

Type	JSON	Value
Binary	B	String value containing the Base64-encoded binary data.
Boolean	BOOL	Either true or false
String	S	String value
Number	N	String with the numerical value
Null	NULL	Should always be true

Collection Types

Type	JSON	Value
List	L	A JSON array, with each element being an attribute with a type.
Map	M	A JSON object, with the keys being the map keys, and the values being an attribute with a type.

Set Types

Type	JSON	Value
Binary Set	BS	A JSON array of Base-64-encoded binary data.
Number Set	NS	A JSON array of string with the numerical values.
String Set	SS	A JSON array of strings.

Sources:

• AttributeValue API documentation: this the definitive guide from AWS.

• DynamoDB Item size and format: more info about the particulars of each attribute type.