Firebase notification records/log API

Solution 1:

As of August 2018, stats for messages sent using the FCM API are now visible from the console. From the Cloud Messaging section, click on the Reports tab. From there, you will be able to filter by message type (notification, data, and all)

It would seem that the Impressions and Opens are still only available for messages sent using the console. But Sends for sure now counts the messages sent using the FCM API.

Reference: https://firebase.googleblog.com/2018/08/in-app-messaging-crashlytics.html

Update: The FCM Diagnostics page has been disabled since last year.

If you have a Play Dev Console account and if your app is in at least Alpha Testing, you can make use of the Diagnostics and Statistics page. However, if you're looking for an API, there is currently no API available for it.

Otherwise, I think most of the details you need (like the payload and time sent) can be logged from your app server alone.

And just to support what you already mentioned in your post, as stated by @FrankvanPuffelen here:

The Firebase Notifications charts only show analytics for messages that were sent using the Firebase Notifications panel.

There is currently no public API to send Notifications to audiences. The web interface in the console is the only way to send them.

There is currently no API to feed your own FCM messages into the Firebase Notifications analytics panels.

Solution 2:

If you want to fetch data on push notification client side you could use the BigQuery exports of Analytics data.

Here is a list of events, as you can see there are several events on notifications, including notification_open and notification_send.

Unfortunately notification_send seems to be available only for Android apps. I don't know why since the Firebase GUI console Message Delivery Report does contain iOS sends as well.