> For the complete documentation index, see [llms.txt](https://docs.n8n.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.n8n.io/connect/create-nodes/build-your-node/reference/base-files/programmatic-style-execute-method.md).

# Programmatic-style execute method

A reference document for the programmatic-style execute() method of the node base file.

The main difference between the declarative and programmatic styles is how they handle incoming data and build API requests. The programmatic style requires an `execute()` method, which reads incoming data and parameters, then builds a request. The declarative style handles requests using the `routing` key in the `operations` object.

The `execute()` method creates and returns an instance of `INodeExecutionData`.

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**Paired items**

You must include input and output item pairing information in the data you return. For more information, refer to [Paired items](/connect/create-nodes/build-your-node/reference/item-linking.md).
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