Enterprise Framework

Software Solutions in the Enterprise

Lambda Node.js Callback


Using the Callback Parameter

The Node.js runtimes v4.3 and v6.10 support the optional callback parameter. You can use it to explicitly return information back to the caller. The general syntax is:

callback(Error error, Object result);


  • error – is an optional parameter that you can use to provide results of the failed Lambda function execution. When a Lambda function succeeds, you can pass null as the first parameter.

  • result – is an optional parameter that you can use to provide the result of a successful function execution. The result provided must be JSON.stringify compatible. If an error is provided, this parameter is ignored.


Using the callback parameter is optional. If you don't use the optional callback parameter, the behavior is same as if you called the callback() without any parameters. You can specify the callback in your code to return information to the caller.

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