The Embrace Metrics API allows you to query your metrics from Embrace using PromQL. A list of supported Standard Metrics can be found here.
Crashes_total / sessions_total will not produce the same value as crash-free session rate. This is because some crashes do not have Session IDs associated with them because things happen, but they happened on a session. We have a background process that attempts to conciliate crashes with the session.
In Metrics API, there are two kinds of metrics: Metrics that we calculate when we receive the request from the customer and metrics that we pre-calculate. For the metrics that we pre-calculate, we don’t have up-to-date data.
daily_crash_free_session_rate, daily_sessions_total, and daily_crashes_total utilize up-to-date data. Crash_free_session_rate is more accurate than crashes total / sessions total.