# Write and create a Lambda@Edge function
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To use Lambda@Edge, you *write* the code for your AWS Lambda function. To help you write Lambda@Edge functions, see the following resources:
+  [Lambda@Edge event structure](lambda-event-structure.md) – Understand the event structure to use with Lambda@Edge.
+ [Lambda@Edge example functions](lambda-examples.md) – Example functions, such as A/B testing and generating an HTTP redirect.

The programming model for using Node.js or Python with Lambda@Edge is the same as using Lambda in an AWS Region. For more information, see [Building Lambda functions with Node.js](https://docs.aws.amazon.com/lambda/latest/dg/lambda-nodejs.html) or [Building Lambda functions with Python](https://docs.aws.amazon.com/lambda/latest/dg/lambda-python.html) in the *AWS Lambda Developer Guide*.

In your Lambda@Edge function, include the `callback` parameter and return the applicable object for request or response events:
+ **Request events** – Include the `cf.request` object in the response.

  If you're generating a response, include the `cf.response` object in the response. For more information, see [Generate HTTP responses in request triggers](lambda-generating-http-responses.md#lambda-generating-http-responses-in-requests). 
+ **Response events** – Include the `cf.response` object in the response.

After you write your own code or use one of the examples, you then create the function in Lambda. To create a function or edit an existing one, see the following topics:

**Topics**
+ [Create a Lambda@Edge function](lambda-edge-create-in-lambda-console.md)
+ [Edit a Lambda function](lambda-edge-edit-function.md)

 After you create the function in Lambda, you set up Lambda to run the function based on specific CloudFront events, which are called *triggers*. For more information, see [Add triggers for a Lambda@Edge function](lambda-edge-add-triggers.md).