Segment, email aliasing and Customer.io
Right now, Customer.io doesn't support alias calls from Segment; they implement
anonymousId to identify users, and it's not possible to connect anonymous user data with a newly created
id in Customer.io.As a result, you might end up with duplicates. You might have come across this issue if:
- You're integrated via Segment and are changing
- You have a list of pre-signup emails that may then create accounts later on.
Why don't you support alias calls?
We want to make sure that the people receiving messages are those who have signed up for your service; however, in some cases, we recognise that this isn't ideal.
How this might happen is: if you send us an identify call with some attributes attached, we first look at the
id associated with that call. If the
id is new, a new user is created with those attributes. If that
id already exists, we update only the attributes that are different compared to the previous call. We do not update or change the
id. So if the
id is new to Customer.io, a new (duplicate) user is created, even if you may have just wanted to update a previous one.
What can I do?
There are a couple of options here, and this depends if you're concerned about duplicates of existing users, or if these customers are new ones that haven't yet signed up.
For existing users
In the cases of existing duplicates, we use the following process:
- Export a CSV of your customers from the People page by clicking on the Export to CSV button.
- Identify the duplicates. We recommend keeping the first instance of each— the one with an older
- Create a new CSV file with all of the user
ids to delete.
- Delete those users with our API.
If these are new users, however, the process is a little more complex. We have a couple options here:
- Do not call identify until the user signs up for an account.
- Filter identify calls so that they're not sent to Customer.io (you can do this by using selective integrations).
Some useful links
- The full list of Segment methods are supported with Customer.io.
- Segment have outlined the only integrations that support the Alias method.
- Our Guide to Mapping User Data is the best resource for more context on how to integrate with Customer.io.
As always, if you need any help with this process or have any questions, please let us know!