Scam. Do not use. Scam, Charged us for inactive users! and even user without emails!!! Also we removed them from our code base, but they were keep creating new profiles and charged us for that.

only email support, which is slow to respond. good luck debugging! [EDIT 2022/07]: their email support is helpful so my original review was too harsh. that said, there's a lot of features still missing that are standard in other email tools. ORIGINAL REVIEW: their only form of customer support is email and it takes them 24+ hours to reply. debugging is a very slow. they should at least open live chat but allowing for limited use of zoom or calls would be delightful. if you are only going to have emails, make sure your support team is responding within hours, not a day or so.

Not a fan of customer io Not a fan of customer io. It is way to expensive, but more importantly the pricing doesn't make any sense. The interface is less than ideal. They request annual contracts.

This is my favourite email automation… This is my favourite email automation service. Kinda hard to figure out at first but they have amazing support.

Data was exposed to third party As a customer of Celsius Network, they used Customer.io to manage contacts. Unfortunately Customer couldn’t handle this responsibility and an employee store their data and shared it with an unauthorized third party.