metadata
contentType: explanation
Data structure
In n8n, all data passed between nodes is an array of objects. It has the following structure:
[
{
// For most data:
// Wrap each item in another object, with the key 'json'
"json": {
// Example data
"apple": "beets",
"carrot": {
"dill": 1
}
},
// For binary data:
// Wrap each item in another object, with the key 'binary'
"binary": {
// Example data
"apple-picture": {
"data": "....", // Base64 encoded binary data (required)
"mimeType": "image/png", // Best practice to set if possible (optional)
"fileExtension": "png", // Best practice to set if possible (optional)
"fileName": "example.png", // Best practice to set if possible (optional)
}
}
},
]
/// note | Skipping the json key and array syntax
From 0.166.0 on, when using the Function node or Code node, n8n automatically adds the json key if it's missing. It also automatically wraps your items in an array ([]) if needed. This is only the case when using the Function or Code nodes. When building your own nodes, you must still make sure the node returns data with the json key.
///
Data item processing
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