This platform is very powerful and has robust features allowing us to have a lot of options in how we want to build campaigns, workflows, and segments. For the majority of projects, as long as we can think of setting something up, customer.io allows us to do so. Review collected by and hosted on G2.com.

Often times it can get laggy and slow, especially for larger campaigns. Every few weeks I encounter issues with 1-2 hours where the entire platform is slow in loading screens which can be frustrating. Review collected by and hosted on G2.com.

The interface and flow builders are super intuitive, and the ability to copy/move flows between different workspaces has meant that it has been quick and easy to build out complicated journeys across different products internally. The onboarding and customer support were great through the pre and post-sales process. Review collected by and hosted on G2.com.

I can't think of any initially, possibly just the sheer scale of features makes it a little difficult to know where to start. We are also dealing with 5+ different data sources, so getting those in has proven tricky - this is more a symptom of tech stacks though rather than the platform. Review collected by and hosted on G2.com.

Customer.io is very powerful and intuitive for designing email campaigns for users from a beginning welcome series to sending out one off transactional emails based on various conditions. Customer.io definitely excels in making it easy to track and use attributes assigned to customers. In addition any time I've had any issues their customer support is top notch. Review collected by and hosted on G2.com.

It can be somewhat expensive for a smaller company that doesn't send out a large volume of emails. The pricing is determined by the number of customers you have, which I find less than ideal, since it feels like you're penalized for having more users, even if you aren't emailing all of them. They do recommend removing inactive or unresponsive users from customer.io, but managing this process is inconvenient, and you never know when you might want to contact those users again. While there are certainly ways to work around this, it still feels like a significant frustration and a kind of penalty for small, growing companies. It would make more sense to focus on the number of emails or notifications sent, rather than the size of your user base. Review collected by and hosted on G2.com.

CIO has been evolving quickly and intuitively, effectively becoming the forcing function at our end to catch up. The visual workflow builders, AI automations and the granular control the platform has been giving over complex journeys and campaigns is unmatched. I've been using the tool for 2+ years now and I’ve never had any complaints. Beyond everything, as a marketer, I think the company as a brand does amazing work - it applies B2C principles of communication seamlessly to an otherwise boring B2B category. It's been a pleasure. Review collected by and hosted on G2.com.

If the platform help with data hygiene and there was more control over segmenting beyond the two set identifiers, it would make a world of difference. Review collected by and hosted on G2.com.

The platform offers impressive flexibility, and the customer support truly stands out as among the best in the industry. They genuinely care about user feedback and actively work on implementing requested features. The documentation is not only beautifully presented but also remarkably thorough, covering even highly specific topics. Review collected by and hosted on G2.com.

I find the platform is probably not as intuitive as it could be, especially since I sometimes see my coworkers struggling with certain aspects. However, I believe this may just be a matter of how much time one has spent using it. I still have a lot to learn myself, but overall, I think the platform is absolutely fantastic. Review collected by and hosted on G2.com.

We use Customer.io for email broadcasts, marketing emails, and newsletters. We’ve also tried Mailchimp before, but with a list of around 50k emails, Customer.io handles everything smoothly and does a great job. I also really like the new Email Content Analysis and Design Studio features, they make it much easier to build emails and quickly check subject lines and content before sending. Both have been very useful for me in day-to-day campaigns. Review collected by and hosted on G2.com.

The only thing I’d like to see improved is the limited font options. It would be great if we could use our website’s font set directly in email campaigns for better brand consistency. Review collected by and hosted on G2.com.

I've been a loyal Customer.io user for several years now, and I continue to be impressed with their service. Recently, Customer.io proactively reached out to me and offered to upgrade my plan from "Legacy" to "Premium" - and amazingly, despite getting access to more advanced features, I'm now paying 30% less! I really respect them for this customer-first approach.

I'm particularly impressed with their Customer Data Platform solution, which allows seamless integration of various data sources into the CRM. This makes it incredibly easy to add new customers, generate events, and manage data flows. It's an excellent solution for technical marketing teams who want to maintain independence without constantly relying on IT resources. Review collected by and hosted on G2.com.

I'm looking forward to seeing continued development of the CDP capabilities. Specifically, Customer.io should consider adding device synchronization features - the ability to add, modify, and manage user devices would be a valuable enhancement to the platform. Review collected by and hosted on G2.com.

Customer.io continues to impress me with how quickly it evolves. The platform now feels even more user-friendly, especially with recent improvements to the visual workflow builder — it’s smoother and makes building complex journeys faster. I really appreciate the expanded analytics and reporting options; they make it easier to see how each step of a campaign performs and to optimize in real time. The new message editor is also a great addition, giving more flexibility for personalization and testing. Combined with its solid segmentation and event-based triggers, it remains one of the most powerful tools for lifecycle marketing I’ve used. Integration with other apps is still seamless, and the overall experience keeps getting better. Review collected by and hosted on G2.com.

Everything’s working great now — I don’t have any improvement suggestions at the moment. Review collected by and hosted on G2.com.

Everything about the platform is straightforward and user-friendly. A fantastic new feature I love is the Design Studio, which makes it incredibly easy to create on-brand templates and ensures we consistently respect our graphic charter. It's a huge time-saver! I highly recommend it to anyone looking for an efficient and reliable messaging solution. Review collected by and hosted on G2.com.

While the platform is excellent, I'd love to see more robust and user-friendly tools for data management. Specifically, a simpler way to identify and delete obsolete or unused customer attributes would be a huge help in keeping our workspace clean and efficient. Review collected by and hosted on G2.com.

I like how Customer.io’s segments make it easy to target the right audience with precision. The ability to create dynamic segments that update in real time based on user behavior or attributes helps ensure messages are always relevant and personalized. It saves time and improves engagement. Review collected by and hosted on G2.com.

A valid downside is that Customer.io charges based on the number of users rather than emails sent. For businesses that send fewer emails to a large audience, a per-email pricing model would be more cost-effective and flexible. Review collected by and hosted on G2.com.