Amazon DynamoDB
API Reference


Creates a new item, or replaces an old item with a new item. If an item that has the same primary key as the new item already exists in the specified table, the new item completely replaces the existing item. You can perform a conditional put operation (add a new item if one with the specified primary key doesn't exist), or replace an existing item if it has certain attribute values. You can return the item's attribute values in the same operation, using the ReturnValues parameter.

When you add an item, the primary key attribute(s) are the only required attributes. Attribute values cannot be null. String and Binary type attributes must have lengths greater than zero. Set type attributes cannot be empty. Requests with empty values will be rejected with a ValidationException exception.


To prevent a new item from replacing an existing item, use a conditional expression that contains the attribute_not_exists function with the name of the attribute being used as the partition key for the table. Since every record must contain that attribute, the attribute_not_exists function will only succeed if no matching item exists.

For more information about PutItem, see Working with Items in the Amazon DynamoDB Developer Guide.

Request Syntax

{ "ConditionalOperator": "string", "ConditionExpression": "string", "Expected": { "string" : { "AttributeValueList": [ { "B": blob, "BOOL": boolean, "BS": [ blob ], "L": [ "AttributeValue" ], "M": { "string" : "AttributeValue" }, "N": "string", "NS": [ "string" ], "NULL": boolean, "S": "string", "SS": [ "string" ] } ], "ComparisonOperator": "string", "Exists": boolean, "Value": { "B": blob, "BOOL": boolean, "BS": [ blob ], "L": [ "AttributeValue" ], "M": { "string" : "AttributeValue" }, "N": "string", "NS": [ "string" ], "NULL": boolean, "S": "string", "SS": [ "string" ] } } }, "ExpressionAttributeNames": { "string" : "string" }, "ExpressionAttributeValues": { "string" : { "B": blob, "BOOL": boolean, "BS": [ blob ], "L": [ "AttributeValue" ], "M": { "string" : "AttributeValue" }, "N": "string", "NS": [ "string" ], "NULL": boolean, "S": "string", "SS": [ "string" ] } }, "Item": { "string" : { "B": blob, "BOOL": boolean, "BS": [ blob ], "L": [ "AttributeValue" ], "M": { "string" : "AttributeValue" }, "N": "string", "NS": [ "string" ], "NULL": boolean, "S": "string", "SS": [ "string" ] } }, "ReturnConsumedCapacity": "string", "ReturnItemCollectionMetrics": "string", "ReturnValues": "string", "TableName": "string" }

Request Parameters

The request accepts the following data in JSON format.


In the following list, the required parameters are described first.


A map of attribute name/value pairs, one for each attribute. Only the primary key attributes are required; you can optionally provide other attribute name-value pairs for the item.

You must provide all of the attributes for the primary key. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide both values for both the partition key and the sort key.

If you specify any attributes that are part of an index key, then the data types for those attributes must match those of the schema in the table's attribute definition.

For more information about primary keys, see Primary Key in the Amazon DynamoDB Developer Guide.

Each element in the Item map is an AttributeValue object.

Type: String to AttributeValue object map

Required: Yes


The name of the table to contain the item.

Type: String

Length Constraints: Minimum length of 3. Maximum length of 255.

Pattern: [a-zA-Z0-9_.-]+

Required: Yes


This is a legacy parameter. Use ConditionExpression instead. For more information, see ConditionalOperator in the Amazon DynamoDB Developer Guide.

Type: String

Valid Values: AND | OR

Required: No


A condition that must be satisfied in order for a conditional PutItem operation to succeed.

An expression can contain any of the following:

  • Functions: attribute_exists | attribute_not_exists | attribute_type | contains | begins_with | size

    These function names are case-sensitive.

  • Comparison operators: = | <> | < | > | <= | >= | BETWEEN | IN

  • Logical operators: AND | OR | NOT

For more information on condition expressions, see Specifying Conditions in the Amazon DynamoDB Developer Guide.

Type: String

Required: No


This is a legacy parameter. Use ConditionExpression instead. For more information, see Expected in the Amazon DynamoDB Developer Guide.

Type: String to ExpectedAttributeValue object map

Required: No


One or more substitution tokens for attribute names in an expression. The following are some use cases for using ExpressionAttributeNames:

  • To access an attribute whose name conflicts with a DynamoDB reserved word.

  • To create a placeholder for repeating occurrences of an attribute name in an expression.

  • To prevent special characters in an attribute name from being misinterpreted in an expression.

Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:

  • Percentile

The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide). To work around this, you could specify the following for ExpressionAttributeNames:

  • {"#P":"Percentile"}

You could then use this substitution in an expression, as in this example:

  • #P = :val


Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.

For more information on expression attribute names, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.

Type: String to string map

Length Constraints: Maximum length of 65535.

Required: No


One or more values that can be substituted in an expression.

Use the : (colon) character in an expression to dereference an attribute value. For example, suppose that you wanted to check whether the value of the ProductStatus attribute was one of the following:

Available | Backordered | Discontinued

You would first need to specify ExpressionAttributeValues as follows:

{ ":avail":{"S":"Available"}, ":back":{"S":"Backordered"}, ":disc":{"S":"Discontinued"} }

You could then use these values in an expression, such as this:

ProductStatus IN (:avail, :back, :disc)

For more information on expression attribute values, see Specifying Conditions in the Amazon DynamoDB Developer Guide.

Type: String to AttributeValue object map

Required: No


Determines the level of detail about provisioned throughput consumption that is returned in the response:

  • INDEXES - The response includes the aggregate ConsumedCapacity for the operation, together with ConsumedCapacity for each table and secondary index that was accessed.

    Note that some operations, such as GetItem and BatchGetItem, do not access any indexes at all. In these cases, specifying INDEXES will only return ConsumedCapacity information for table(s).

  • TOTAL - The response includes only the aggregate ConsumedCapacity for the operation.

  • NONE - No ConsumedCapacity details are included in the response.

Type: String

Valid Values: INDEXES | TOTAL | NONE

Required: No


Determines whether item collection metrics are returned. If set to SIZE, the response includes statistics about item collections, if any, that were modified during the operation are returned in the response. If set to NONE (the default), no statistics are returned.

Type: String

Valid Values: SIZE | NONE

Required: No


Use ReturnValues if you want to get the item attributes as they appeared before they were updated with the PutItem request. For PutItem, the valid values are:

  • NONE - If ReturnValues is not specified, or if its value is NONE, then nothing is returned. (This setting is the default for ReturnValues.)

  • ALL_OLD - If PutItem overwrote an attribute name-value pair, then the content of the old item is returned.


The ReturnValues parameter is used by several DynamoDB operations; however, PutItem does not recognize any values other than NONE or ALL_OLD.

Type: String


Required: No

Response Syntax

{ "Attributes": { "string" : { "B": blob, "BOOL": boolean, "BS": [ blob ], "L": [ "AttributeValue" ], "M": { "string" : "AttributeValue" }, "N": "string", "NS": [ "string" ], "NULL": boolean, "S": "string", "SS": [ "string" ] } }, "ConsumedCapacity": { "CapacityUnits": number, "GlobalSecondaryIndexes": { "string" : { "CapacityUnits": number } }, "LocalSecondaryIndexes": { "string" : { "CapacityUnits": number } }, "Table": { "CapacityUnits": number }, "TableName": "string" }, "ItemCollectionMetrics": { "ItemCollectionKey": { "string" : { "B": blob, "BOOL": boolean, "BS": [ blob ], "L": [ "AttributeValue" ], "M": { "string" : "AttributeValue" }, "N": "string", "NS": [ "string" ], "NULL": boolean, "S": "string", "SS": [ "string" ] } }, "SizeEstimateRangeGB": [ number ] } }

Response Elements

If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.


The attribute values as they appeared before the PutItem operation, but only if ReturnValues is specified as ALL_OLD in the request. Each element consists of an attribute name and an attribute value.

Type: String to AttributeValue object map


The capacity units consumed by the PutItem operation. The data returned includes the total provisioned throughput consumed, along with statistics for the table and any indexes involved in the operation. ConsumedCapacity is only returned if the ReturnConsumedCapacity parameter was specified. For more information, see Provisioned Throughput in the Amazon DynamoDB Developer Guide.

Type: ConsumedCapacity object


Information about item collections, if any, that were affected by the PutItem operation. ItemCollectionMetrics is only returned if the ReturnItemCollectionMetrics parameter was specified. If the table does not have any local secondary indexes, this information is not returned in the response.

Each ItemCollectionMetrics element consists of:

  • ItemCollectionKey - The partition key value of the item collection. This is the same as the partition key value of the item itself.

  • SizeEstimateRange - An estimate of item collection size, in gigabytes. This value is a two-element array containing a lower bound and an upper bound for the estimate. The estimate includes the size of all the items in the table, plus the size of all attributes projected into all of the local secondary indexes on that table. Use this estimate to measure whether a local secondary index is approaching its size limit.

    The estimate is subject to change over time; therefore, do not rely on the precision or accuracy of the estimate.

Type: ItemCollectionMetrics object


For information about the errors that are common to all actions, see Common Errors.


A condition specified in the operation could not be evaluated.

HTTP Status Code: 400


An error occurred on the server side.

HTTP Status Code: 500


An item collection is too large. This exception is only returned for tables that have one or more local secondary indexes.

HTTP Status Code: 400


Your request rate is too high. The AWS SDKs for DynamoDB automatically retry requests that receive this exception. Your request is eventually successful, unless your retry queue is too large to finish. Reduce the frequency of requests and use exponential backoff. For more information, go to Error Retries and Exponential Backoff in the Amazon DynamoDB Developer Guide.

HTTP Status Code: 400


The operation tried to access a nonexistent table or index. The resource might not be specified correctly, or its status might not be ACTIVE.

HTTP Status Code: 400


Put an Item

The following example puts a new item into the Thread table, but only if there is not already an item in the table with the same key.

Sample Request

POST / HTTP/1.1 Host: dynamodb.<region>.<domain>; Accept-Encoding: identity Content-Length: <PayloadSizeBytes> User-Agent: <UserAgentString> Content-Type: application/x-amz-json-1.0 Authorization: AWS4-HMAC-SHA256 Credential=<Credential>, SignedHeaders=<Headers>, Signature=<Signature> X-Amz-Date: <Date> X-Amz-Target: DynamoDB_20120810.PutItem { "TableName": "Thread", "Item": { "LastPostDateTime": { "S": "201303190422" }, "Tags": { "SS": ["Update","Multiple Items","HelpMe"] }, "ForumName": { "S": "Amazon DynamoDB" }, "Message": { "S": "I want to update multiple items in a single call. What's the best way to do that?" }, "Subject": { "S": "How do I update multiple items?" }, "LastPostedBy": { "S": "" } }, "ConditionExpression": "ForumName <> :f and Subject <> :s", "ExpressionAttributeValues": { ":f": {"S": "Amazon DynamoDB"}, ":s": {"S": "How do I update multiple items?"} } }

Sample Response

HTTP/1.1 200 OK x-amzn-RequestId: <RequestId> x-amz-crc32: <Checksum> Content-Type: application/x-amz-json-1.0 Content-Length: <PayloadSizeBytes> Date: <Date> { }

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following: