Common Query Parameters

All Query operations share a set of common parameters that must be present in each call.

Name	Description	Required
`Action`	Indicates the action to perform. Example: `RunInstances`	Yes
`Version`	The API version to use, as specified in the WSDL. Example: `2009-10-31`	Yes
`AWSAccessKeyId`	The Access Key ID for the request sender. This identifies the account which will be charged for usage of the service. The account with which the Access Key ID is associated must be signed up for Amazon EC2, or requests will not be accepted. `AKIADQKE4SARGYLE`	Yes
`Timestamp`	The date and time at which the request is signed, in the format YYYY-MM-DDThh:mm:ssZ. For more information, go to ISO 8601. Example: `2006-07-07T15:04:56Z`	Yes
`Expires`	The date and time at which the signature included in the request expires, in the format YYYY-MM-DDThh:mm:ssZ. Example: `2006-07-07T15:04:56Z`	Yes
`Signature`	The request signature. For more information, go to the Amazon Elastic Compute Cloud Developer Guide. Example: `Qnpl4Qk/7tINHzfXCiT7VbBatDA=`	Yes
`SignatureMethod`	The hash algorithm you use to create the request signature. Valid values: `HmacSHA256` \| `HmacSHA1`. For more information, go to the Amazon Elastic Compute Cloud Developer Guide. Example: `HmacSHA256`	Yes
`SignatureVersion`	The signature version you use to sign the request. Set this value to `2`. For more information, go to the Amazon Elastic Compute Cloud Developer Guide. Example: `2`	Yes

	Note
	The `Timestamp` parameter can be used instead of `Expires`. Requests must include either `Timestamp` or `Expires`, but cannot contain both.

Parameter values must be URL-encoded. This is true for any Query parameter passed to Amazon EC2 and is typically necessary in the Signature parameter. Some clients do this automatically, but this is not the norm.