It could be because of the differences described here between fetching events and the UI’s reporting:

https://developers.klaviyo.com/en/reference/reporting_api_overview

You may be using our Query Metric Aggregates endpoint to export reporting data for campaigns and flows. It’s important to note that data from the Query Metric Aggregates endpoint does not match the data reflected in the Klaviyo UI. While this endpoint allows you to filter and group campaign and flow data based on the time an event occurred, performance in the Klaviyo UI is calculated based on send date. We recommend our Reporting API to achieve this use case, which is built to fetch 1:1 matches of data shown in the Klaviyo UI.

Hi ​@saulblum , what is meaning of “send date” where could i find that on API?

“Send date” is when a given campaign or flow message was sent, vs. when the open or click event happened, which is what calls like Query Metric Aggregates is counting.

​@saulblum : Any ways i can link data from “Query Metric Aggregates” to send_date? because in query metric aggregates i only have event_date?

No, because Query Metric Aggregates is measuring when the events like Clicked Email happen, not when the original messages were sent.

That’s what the reporting API is for.