Trying to migrate from MailChimp to Zoho Campaigns, and we add tags to a lot of our contacts. These tags are mostly unorganised (hence tags, not contact attributes) and internal markers used for segmentation. They are added/removed automatically over the contact's lifetime.

I could use a multi-picklist custom field in Zoho Campaigns, but that means manually updating said field every time we need a new tag, which are generated on the fly, which means having to automate updating the custom field settings... which is frankly stupid.

Where's the documentation that tells me the POST request I need to make to add a tag to a contact?