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InfluxDB
Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
While you wait, iMessage on Android already exists. Here are two projects that run a server on macOS and are both open-source (code here and here). If you don't have a Mac, you can still use a jailbroken iOS with SMServer (code here), and use the PWA on your Android phone.
NOTE:
The number of mentions on this list indicates mentions on common posts plus user suggested alternatives.
Hence, a higher number means a more popular project.