I would like to tag some emails using the SOAP API with a tag in a way that is not visible to end users. The tag “name” can be the same, but the tag “value” will be different for each email we tag. What would you suggest? Can we set some type of custom property, insert a X- header in MIME content, etc.? We need to both a/ tag emails (each with a different value) and b/ efficiently retrieve all tag values for tagged emails in a folder. We cannot afford to retrieve content for all emails in a folder just to be able to get tag values back.
Thanks in advance for your answer,