When we announced custom fields support was live, we had some great requests on what should come next. One of the most requested features was the ability to add custom field data from the API.

I'm happy to announce that custom field support in the API is now live. Check out the full documentation for some sample code on how to get started with this new method.

Now that this one is out of the way, we're hard at work on the next big custom fields extension - segmentation. This functionality will make it easy for your clients to send much more targeted campaigns by creating "segments" of subscribers based on custom field data. We're hoping to have this feature out the door in the next few weeks. Thanks for your patience.