# CallbackStartedDetails
<a name="API_CallbackStartedDetails"></a>

Contains details about a callback operation that has started, including timing information and callback metadata.

## Contents
<a name="API_CallbackStartedDetails_Contents"></a>

 ** CallbackId **   <a name="lambda-Type-CallbackStartedDetails-CallbackId"></a>
The callback ID. Callback IDs are generated by the `DurableContext` when a durable function calls `ctx.waitForCallback`.  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 1024.  
Pattern: `[A-Za-z0-9+/]+={0,2}`   
Required: Yes

 ** HeartbeatTimeout **   <a name="lambda-Type-CallbackStartedDetails-HeartbeatTimeout"></a>
The heartbeat timeout value, in seconds.  
Type: Integer  
Valid Range: Minimum value of 0.  
Required: No

 ** Timeout **   <a name="lambda-Type-CallbackStartedDetails-Timeout"></a>
The timeout value, in seconds.  
Type: Integer  
Valid Range: Minimum value of 0.  
Required: No

## See Also
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For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/lambda-2015-03-31/CallbackStartedDetails) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/lambda-2015-03-31/CallbackStartedDetails) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/lambda-2015-03-31/CallbackStartedDetails)