> For the complete documentation index, see [llms.txt](https://docs.feedotter.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.feedotter.com/newsletters/content-sources/json-xml-api/custom-data-fields.md).

# Custom Data Fields

When you create a content source, add any custom data elements.  Copy down the "label" value as this is how you will access the data in your email code.

In the example below we have setup 1 custom data field labeled "newfield1"

<div align="left"><figure><img src="/files/c8tgPdEBcoW6X9skwW6y" alt=""><figcaption></figcaption></figure></div>

You can access the data in this field in your email code using the following token:

```
//replace "newfield1" with the label you gave to your custom data element
[[post.custom.newfield1.value]]
```

When curating your newsletter, you can now edit the value of your custom field on the Edit Content Block UI via the Edit Custom Details tab.

<div align="left"><figure><img src="/files/6LOisqqlrryuBuFUfwSr" alt=""><figcaption></figcaption></figure></div>

The updated value appears in the preview:

<div align="left"><figure><img src="/files/ah92OYeMXv2TRZEfV2Hd" alt=""><figcaption></figcaption></figure></div>


---

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