Customer.io Track Segments API
Manual segments are lists of people that you incorporate using the API or by uploading CSVs. You can add people to, or remove people from, manual segments with these endpoints. These endpoints do _not_ let you modify data-driven segments. **NOTE**: These endpoints do not yet support workspaces that use both `email` and `id` as identifiers. A segment must exist before you can add people to it. You can create manual segments using the [App API `/segments` endpoints](/api/#operation/createManSegment).