Hello @Adam Frauts,

Great question!

@Spark Bridge Digital LLC, one of our Community Champions actually discussed a similar topic int heir Community post below:

Third-party deliverability tools can be helpful to give you an overview of your deliverability but shouldn’t be used as the source of truth. That being said, there are some third-party deliverability tools that are reputable to help in informing your decisions. You can find this list from the Third-Party Deliverability Monitoring Tools Help Center article.

Instead, we suggest reviewing and analyzing your own deliverability performance. In my experience, unless you’re on a dedicated sending IP, using those tools to monitor your sending IP will typically raise some false alarms indicating that you’re sending from a blocklisted IP address. Similar to many ESPs, Klaviyo’s sending IP address are constantly in flux. 

Due to the large number of sending IP addresses Klaviyo has and rotates, IP addresses that are recognized as blocklisted will be regularly de-listed as we continually monitor our IP performances. 

I’ve also included some additional resources below that I believe could be helpful in monitoring your own deliverability including our recommended performance ranges in the chart below:

• How to Monitor Email Deliverability Performance
• Understanding Deliverability Best Practices
• Guide to Email Deliverability
• How to Strengthen Your Sender Reputation
• Guide to Warming Your Sending Infrastructure

I hope this helps!

David